Magneticall aduertisements: or Diuers pertinent obseruations, and approued experiments, concerning the natures and properties of the load-stone Very pleasant for knowledge, and most needfull for practise, of trauelling, or framing of instruments fit for trauellers both by sea and land. Whereunto is anexed a breife discouerie of the idle animaduersions of Mark Ridley Dr. in Physicke, vpon a treatise entituled Magneticall aduertisements.

Magneticall aduertisements: or Diuers pertinent obseruations, and approued experiments, concerning the natures and properties of the load-stone Very pleasant for knowledge, and most needfull for practise, of trauelling, or framing of instruments fit for trauellers both by sea and land. Whereunto is anexed a breife discouerie of the idle animaduersions of Mark Ridley Dr. in Physicke, vpon a treatise entituled Magneticall aduertisements.

Table of contents

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Title page

TO THE RIGHT WORSHIPFVLL, DIScreet, and learned Gentleman, Sir DVDLEY DIGGES Knight.

THE PREFACE to the Reader.

Contents of this Treatise.

MAGNETICALL Aduertisements.

CHAP. I. Of the magneticall power and force of the whole Globe of the Earth.

CHAP. II. The ambiguity of the North and South ends of Magnets and Magneticall bodies explained, and Doctor Gilbert therein defended.

CHAP. III. Certaine generall obseruations of the nature and properties of the Loadstone.

CHAP. IIII. By what meanes the chiefe points of any Magnet of what forme soeuer may easily be found out.

The second way.

The third way.

The fourth way.

The fift way.

A sixth way.

CHAP. V. The manner of capping both with single and double cappes and the nature of them.

CHAP. VI. Of cementing and peecing of Loadstones.

CHAP. VII. Of the variation of the Magneticall Needle with the Appurtenances therevnto belonging.

CHAP. VIII. A discouery of errours committed in making and touching Magneticall Needles and Wyars of sayling Compasses, with an aduise for the true and right making and touching of them.

CHAP. IX. Of the touching with a Laadstone capped and without the cappe.

CHAP. X. Of the fashioning of the compasse needle.

CHAP. XI. A Sayling Compasse fitted for obseruing at Sea the variation, amplitude of either sunne or starres, capes or trendings, &c.

The Vses.

CHAP. XII. A comparison of the seuerall vses of the Horizontall and inclinatory Magneticall Needles.

To the Worshipfull my good friend, Mr. William Barlow at Easton by Winchester.

Faults escaped.

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Title page

TO THE RIGHT NOBLE AND WORthy minded industrious Gentlemen, and others who are any way addicted vnto MAGNETICALL Knowledge.

§

§

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MAGNETICALL Aduertisements: OR

DIVERS PERTINENT obseruations, and approued experiments, concerning the natures and properties of the Load-stone.

Uery pleasant for knowledge, and most needfull for practise, of trauelling, or framing of Instruments fit for Trauellers both by Sea and Land.

Whereunto is annexed a breife Discouerie of the idle Animaduersions of MARK RIDLEY Dr. in Physicke, vpon this Treatise entituled Magneticall Aduertisements.

ACTS 17. 26. He hath made of one bloud all nations of men for to dwell on the face of the earth, and hath determined the times before appointed, and the bounds of their habitation, that they should seeke the Lord, &c.

The second Edition.

LONDON, Printed by Edward Griffin for Timothy Barlow, and are to be sold at his shop in Pauls Church-yard, at the signe of Time. 1618.

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TO THE RIGHT WORSHIPFVLL, DIScreet, and learned Gentleman, Sir DVDLEY DIGGES Knight.

SIR, the nature, powerfulnesse, and strange properties of the loadstone are such, that the more they are known, the more they are iustly admired in their most liuely expressing that infinite power, and goodnes of our God, who hath created so precious a Iewell for the profitable vse of man, and for the enlarging, and setting forth of his owne glory. Into the search of which admirable and secret vertues [Page] my selfe by the space of these forty yeeres, haue somewhat entred (as my leasure and occasions would serue, and at by times) partly by reading other mens writings, and partly by my owne industrie and practize: Whereby what I haue collected, and found, this little Treatise will shew. Which, whether it be any thing, or nothing, I do referre vnto the iudicious Readers consideration, but in special to your fauorable construction, and good acceptance.

Many yeeres since diuers of my good friends, and among them some honourable persons, were very desirous that I should publish such obseruations as I had collected, both before, and also after the setting forth of D. Gilberts booke: And none more earnest herein then D. Gilbert himselfe, vnto whom I communicated what I had obserued of my selfe, and what I had built vpon his foundation of the Magnetisme of the earth. Both which hee liked well and wished me to publish them, as I remember at the time of our priuate conference, as may further appeare by letters that I receiued from him; which I haue to shew vnder his owne hand.

[Page]But aboue all others, the perswasions of that learned honourable Gentleman, Sir Thomas Challenor, late Chamberlaine vnto the Mirrour of honour Prince Henry preuailed most with me. Vnto whom I was all the time that I attended that Prince his highnesse, for his loue and curtesie, much beholding. Whereupon about seauen yeeres since I deliuered vnto him this Treatise, finished almost as now it is, sauing some few additions vpon necessary occasions. But that Copie was either mislaied or embeseled, that he lost it; About three yeeres since he sent earnestly vnto mee for an other Copie: which also he receiued, promising me by his letters, that within three months hee would put that to the presse, and that it should be carefully and correctly performed: But what is become euen of that also I know not: Only this I am sure of that I haue met with many portraitures of my Magneticall implements, and diuers of my propositions set abroad in print in another mans name, and yet some of them not rightly vnderstood by the partie vsurping them.

Now that it hath pleased God to take [Page] Sir Thomas Challenor and that vpon enquirie I can heare no tidings of those my lost labours, and knowing that diuers are very desirous to see them, I haue once againe reuiued my scattered papers, collected them together, & made choice of your selfe to whom to entitle (according vnto our vsuall curtesies) these magneticals; your worthy selfe I say in many respects: First, because your rare learning ioin'd with so great pietie, accompanied with so pleasing a carriage of your selfe towards euerie man is such, as causeth all good men which know you, to loue you, by force of a naturall sympathy not vnlike the appetite of concourse & coniunction whereby our very Magnets doe affect their proper obiects. And this was verie conspicuous in our renowned iudicious Prince Henry, who loued you singularlie well for your vertues, and delighted no lesse to conferre with you for your knowledge in matters appertaining vnto Discoueries and Cosmographicall learnings, in the which his highnes was more then vulgarly skilfull.

Another is, the glorious fauour which I see reflected vpon you from that most reuerend [Page] and singular ornament of our Church and State, reioycing in Gods blessing of his labors in your education: like as God hath hitherto blessed him in all things, and not onely my prayers and such as I am who are so much bounden vnto him, but the praiers of many thousands that neuer saw him, will not cease to beseech the Almightie long to preserue him. and alwaies to prosper him in his godly proceedings: Wherefore this extraordinary respect which he hath vnto you, both is and must be a commanding motiue vnto mee to shew my good will by the best poore meanes that I can toward you.

Yet one more I haue, which is this: That whereas a worthy societie of Gentlemen and Marchants is very highly and iustly commended and honoured of all men, for their great charges in their constant and indefatigable proceedings, for discoueries of vnknown passages to new Countries and Nations, for the further aduancement of Gods glorie, the honour of our King, and principall benefit of the whole Kingdome; In remembring of those honourable attempts, you must in no wise be [Page] forgotten, and especially in a Treatise mentioning the vertues, and properties of the Loadstone, being the leader and guide to these admirable exploits, who besides your souud knowledge herein, doe with great constancie ioine both your purse and counsaile for the atcheiuing of them, yea and that without expectation, or hope of priuate gaine, but onely of your noble genorositie, knowing full well, that the aduancement of Gods glorie is absolutely of it selfe the greatest gaine with a contented minde; Wherewith, he that onely is all-and selfe-sufficient, enrich you more and more in this world, and to your eternall happinesse, most abundantly and perfectly satisfie you, by making you drinke of the riuer of his pleasures in the world to come; Amen.

Yours with all hearty affection

WILLIAM BARLOWE.

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THE PREFACE to the Reader.

THat wonderfull propertie of the body of the whole earth, called the Magneticall vertue (most admirably found out, & as learnedly demonstrated by Doctor Gilbert Phisitian vnto our late renowned Soueraigne Queene Elizabeth of happy memory) is the very true fountaine of all Magneticall knowledge. So that although certaine properties of the Loadstone were knowne before, yet all the reasons of those properties were vtterly vnknowne, and neuer before reuealed (as I take it) vnto the sonnes of men. And although as yet many doe doubt and mistrust that the earth it selfe hath no such vertue, I doe nothing wonder at it, because before I read his learned workes, and had tried many of his experiments with mine owne hands, and had conferred with great Trauellers, and pervsed the obseruations of our chiefest Nauigators both for their variations, and declinations, I neuer beleeued it my selfe. But this I may truely affirme that searching with diligence his first fiue bookes, and making triall of all those propositions which I iudged to be of importance, I alwaies found the maine drift, touching this point, certaine, constant, and agreeable to the diligent obsernations of diuers men of experience; although in some other [Page] matters of the Loadstone his experiments and mine did sometimes disagree, as I signified to himselfe in his life time, which he did take in very good part, as I haue yet his owne letters to shew. But concerning his sixth Booke entreating of the motion of the earth, I thinke there is no man liuing farther from beleeuing it, than my selfe, being nothing at all perswaded there vnto, by the reasons of other men, which he alledgeth, and as little or lesse (if it were possible) by those his inventions, endeuouring to proue the motion of the earth by the earthes Magneticall force and vertue.

Amicus Socrates, Amicus Plato, sed magis amica veritas is the onely cause why I doe embrace his iudgment, in the one, and refuse it in the other, in matters of this nature following this Rule:

Nullius addictus iurare in verba Magistri.

But to returne to the Magnetisme of the whole earth, I doe hold it to be one of the rarest, and excellent est inventions, and the best followed by him, with euident proofes and of the greatest consequence for the admirable art of Nauigation that euer was found out since the Creation of the world, so that it may well be said of him touching that point.

Exegit monumentum aere perennius

Regali (que) situ pyramidū altius,

in respect of the manifold vse and commoditie thereof in the doings of this life. The properties of the Magnet seruing not onely for Sea-affaires, but also for trauelling by Land in vaste and solitarie deserts, for moueable Sun-dyalls in all places of the world, for the more ready and exact Chorographie of any Countrey, or the true plotting of any ground, and for the following of any Minerall veyne that is voide of Iron vnder the earth, for Pioners and diggers in Mines. [Page] And in all this appeareth the wonderfull power and goodnes of God who hath vouchsafed to reueale vnto the weake knowledge of man now towards the end of the world, his admirable treasure, before vnknowne, of his powerfull Creation, by effect so plaine vnto the mean est capacitie: And that out of a base, contemptible and dead creature, as it seemeth to be, and yet filled with such excellent and wonderfull vertue, that all the Gemms of the world, haue not the like; neither if it were wanting could supply the want thereof, or counter vaile the benefit that it bringeth to the life of man.

Claudianus (a famous Poet) well nere twelue hundred yeares since, saith as much in commendation of the Magnete, when as yet the Serediticall or Iron-drawing property thereof was onely knowne.

—Lapis est cognomine Magnes

Decolor, obscurus, vilis &c.

And againe,

Sed noua si nigri videas miracula saxi,

Tunc superat pulchros cultus, & quicquid Eoïs

Indus littoribus rubra scrutatur in algâ.

But what would he not haue said, had hee seene the true closset indeed of all Magneticall miracles vnlocked, and in glorious manner set wide open as now it is at this day.

Many of our Nation both Gentlemen and others of excellent witts and louers of these knowledges, not able to read Doctor Gilberts Booke in Latin, haue bin (euer since the first publishing thereof) exceeding desirous to haue it translated into English, but hitherto no man hath done it, neither (to my knowledge) as yet goeth about any such matter, whereof one principall cause is that there are very few [Page] that vnderstand his Booke, because they haue not Loadstones of diuers formes, but especially round ones: Also such versory needles fitly framed, and artificially placed vpon their pins, and other such implements, as he doth there prescribe, wherewith being furnished, as they read his propositions in words, they might still see the truth of them in the things themselues, according as himselfe forewarneth that these skills must be learned Ex rebus ipsis non solum ex libris, out of the things themselues and not onely out of Bookes. A second cause may be for that there are diuers words of Art in the whole course of this booke proper to this subiect, and fit to the explanation of his figures and diagrammes which cannot be vnderstood but by the helpe of the Mathematicks, and good trauelling in the Magneticall practise.

Moreouer his alleadging of other mens erroneous opinions concerning this Argument, and his confutations thereof, may seeme at the first to a yong beginner somewhat harsh and tedious. Both which I suppose in the English translation (if any were) might well be omitted: like as in this my Treatise I thinke it not altogether so pertinent to handle them all.

And a sport it is to behold diuers of smart witts, and such as weene themselues to be so great Clerkes, that they will aduenture boldly to dispute de omni scibili, how miserably they runne their witts on ground, when onely by a slender reading ouer of his booke, or most commonly some part thereof, they will take vpon them to define, controule, and discourse of those matters fearing nothing more than that of the Poet,

—mihi turpe relinqui est

Et quod non didici sane nescire fateri.

[Page]For being vrged by diuers of our Gentlemen (among whom these knowledges are had now a daies in some request) somewhat they must speake, which must be either superciliously to scorne such things, as vanities, because themselues vnderstand them not, or else with slender ostentation to blunder out their masked ignorance, supposing it to be inough for them to say that they haue read Dr. Gilberts Booke, and so to vse that for a Supersedeas to acquite them of any farther inquirie. But many, being now at length weary to take such counterfeit shewes for good payment, doe seriously seeke to haue some sound knowledge of the things themselues, and not to depend vpon other mens extravagant disputes, but to be their owne iudges in matters that concerne themselues, and are subiect to their owne senses and reasons, and especially because some of them must aduenture their whole estates, yea and also their liues vpon the right vnderstanding of some Magneticall conclusions.

Wherefore vpon the earnest longing of certaine mine Honorable and Worshipfull freinds, and for the singular loue that I beare to the louers and practizers of the worthy Art of Nauigation, and to satisfie the commendable desires of such as like to haue some insight (though themselues be not praectizers in these matters of admirable knowledge, and great vtilitie) I haue vndertaken to contriue all the cheifest points of this most necessary skill, and the vse of them in this short Treatise.

Not meaning to translate Doctor Gilberts booke, but to take those thing out of it which I shall thinke fit for this purpose, which are onely the Magnetisme of the whole earth, and some of the consequents thereof, and to adde the rest of mine own industry: Wherin I may be bold after asort [Page] to challenge a right, as hauing endeuoured to get some insight in this argument (a matter well knowne to diuers) aboue the space of twenty yeares ere Doctor Gilberts book saw light. And in very deed I communicated many of my obseruations with him, aboue one whole yeare before he put it out in print. To be short, of all that I shall set downe in this Treatise my request is, that the Reader will admit nothing but that which shall be confirmed by good reason, or vndoubted experiments. And I purpose (God willing) to tye my selfe, as strictly vnto this rule as euer any man did that hath written of the like argument, making it euen a matter of conscienae to deliuer any thing herein for certaintie, that my selfe shall not know to be sound. And so by this meanes shall I neither abuse the Reader with any vntrue assertion, nor iniurie so certaine and so excellent a knowledge with any doubtfull or vnapproueable conclusions.

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Contents of this Treatise.

CHAP. I. OF the Magneticall power of the whole Globe of the Earth.

CHAP. II. Of the ambiguitie of the North and Sooth ends of Magnets and Magneticall bodies explained, and Doctor Gilbert therein defended.

CHAP. III. Certaine generall obseruations of the nature and properties of the Loadstone.

CHAP. IIII. By what meanes the chiefest points of any Magnet of what forme soeuer may easily be found out.

CHAP. V. The manner of Capping both with single and double Capps, and the nature of them.

CHAP. VI. Of cementing and peicing of Loadstones

CHAP. VII. Of the variation of the Magneticall Needle with the Appurtenances therto belonging.

CHAP. VIII. A discouery of Errors committed in the making and touching Magneticall Needes and Wiars of sayling Compasses, with an aduise for the true and right making and touching of them.

[Page]CHAP. IX. Of the touching with a Loadstone capped and without the Cappe.

CHAP. X. Of the fashioning of the Compasse Needle.

CHAP. XI. A Sayling Compasse fitted for obseruing at Sea the variation, amplitude of either Sunne, or Starres, Capes, or trendings, &c.

CHAP. XII. A comparison of the seuerall vses of the Horizontall, and Inclinatory Magneticall Needles.

A true copie of one of D. Gilberts letters written to the Author, concerning his Magneticall Experiments.

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MAGNETICALL Aduertisements.

CHAP. I. Of the magneticall power and force of the whole Globe of the Earth.

COncerning the Magneticall force of the whole body of the Earth, I haue selected these experiments to proue it.

Take any peece of solid earth that hath some toughnesse to hold together, and will abide the fire, as any sort of clay, or bricke (which somtimes was clay) fashion it in such manner that it bee vniformely extended towards both ends (the Ouall or long figure is fittest for our purpose) put it into a fire of charcoles, increasing the heat by little and little, and at the length with often blowing, make it throughly as red hot as you can: let [Page] it remaine so for the space of halfe an houre, or more, that thereby all superfluous moisture may be consumed, and aduerse qualities separated from it, then take it forth, and let it coole of it selfe, being first set North and South, with either end answerable to the variation of the place, not paralell vnto the Horizon, but eleuated answerable to the Latitude as nere as you can. Certaine it is that this peece of earth thus ordered, will sensibly shew you that it hath true Magneticall vertue. But here before I proceed any farther I must deliuer vnto you a necessary obseruation: There are two kindes of Attractions (as they are commonly called) the one Magneticall, the other Electricall. The Magneticall hath alwaies speciall respect vnto the North & South points of the Magnete or Magneticall body. The Electricall body hath no manner of respect vnto any one point of the Electricall body, more than another: And by this difference these two kinds of Attractions are easily discerned; As also by this, looke what end of the Magneticall needle the one end of the Magnet doth draw, the other will chase away; but the Electricall body draweth alike at all ends. And thirdly after this sort, lapp this Electricall body in a paper and it will draw nothing at all, but interposition of brasse or of a stone wall within the orbe of the Magnets vertue, doth nothing weaken the same, or hinder his effect towards his peculiar obiect. Notwithstanding (to speake properly) Attraction pertaineth onely to Electricall bodies, because the whole attractiue vertue is onely in the Electricall body it selfe, and nothing at all in the thing that is attracted. The Attraction [Page] (commonly so called) of the Loadstone is rightly to be termed, Concursion, Confluence, or Coition, because it is the running or vigorous meeting together of two Magneticall bodies hauing a mutuall inclination the one to ioyne with the other, or by any other name, bearing like sense. For the true knowledge thereof, being but lately as a stranger arriued amongst vs, common vse

(Quempenes arbitrium est, & ius & normal loquendi.) hath as yet scant suted it, with a conuenient name to expresse this property; So that Magneticall Concursion is neuer but betweene two bodies, such as both of them are Magneticall; As of one Loadstone with another, or of a Loadstone with yron or steele, or yron oare if it be prepared, or betweene two peeces of yron or steele that are reuiued with a Loadstone; for indeed the Loadstone can but reuiue, and multiply Magneticall force in a body that naturally hath it in some measure before: but cannot infuse it into any thing, that before is vtterly voide of it, as of mettals, in yron or steele, and not in gold, siluer, brasse, &c. Electrum in this argument is named that which is either Amber in substance, or at the least of the quality, and that Amber, being rubbed, hath, to take vp moats, feathers, strawes, sticks, and other small things. The which property is also in ieate, brimstome, hard waxe, (if it be smooth) and in infinite other things both naturall and compound; all which because of that qualitie in this argument are termed Electricall bodies, and their taking vp of things is called Electricall attraction, hauing onely a slender resemblance, and no truth of the Magneticall qualitie. [Page] But that aboue-mentioned peece of earth, prepared in such sort as is before prescribed, will by Magneticall concursion shew it selfe to be a true Magneticall body. For the one end of the Magneticall needle will couet towards the one of the prepared masle, and flie from the other. And contrariwise also, though it will do both but weakely, not with power comparable to a naturall Loadstone, yet as truely as that. That end which cooled toward the South, will draw the true North end of the needle, and that end which cooled toward the North will draw the true South end of the needle. If so be as yet you will haue another infallible argument, doe thus: Marke what end draweth the North end of the needle, afterward put the new made Magnet into the fire againe, and when it hath been glowing for the space of halfe a quarter of an houre, take it out and coole it being placed with that marked end toward the North, most assuredly that end now will draw the South end of the needle, & the North end of the needle will shun it, which before approached vnto it. The reason here of is, because the fire hauing abolished all the former Magneticall qualitie of that masse wherewith it was in a contrary position affected in the former cooling, now leaueth it apt and fit to receiue any other new impression: which presently it taketh againe either regularly, if in the cooling it be placed with the ends to the North and South, or (if it be placed otherwise) confusedly, by the Magneticall force and vertue of the whole body of the earth, by regular and confused, this is the meaning. Take any lump of earth, or any brick-bat ordered in this sort, certaine [Page] it is that this lumpe of earth or bricke-bat hath some magneticall vertue therein, yet so feeble and weake, that our sence cannot discerne it, because of the vnfitnesse of the forme, and the confused dispersion of that weake force, through the whole body thereof. Then suppose you will bring either of these into an extended ovall forme, which is most apt (as before I said) for any body magneticall to shew his force, yet this will helpe it nothing at all of it selfe, as you may easily make experience in euery Loadstone. For if you take a loadstone of a confused forme, it is not inough to bring it into a conuenient ovall, except with diligence you reserue the points of the North and South in the two ends thereof, for if you leaue the points in the sides you marre it with this ovall forme. For the stone will not lightly be of one quarter of the force, it was ofbefore; For the ovall forme giueth it no vertue, but is the fittest for it to shew the vttermost of that strength, which of it selfe it had before, if you obserue the due points, and not otherwise. But in this earth and bricke it is not possible to finde the due points in such sort as you may in a Loadstone, because of the weaknesse of the magneticall force therein contained. And therefore you cannot bring that into a regular ovall forme, to haue the due points in the very ends. But if you first make it into an ovall forme, and by the fire take away the confused magneticall force, and all other peruerse qualities thereof, that being by nature a magneticall body in his cooling before specified, receiueth presently by that vnresistable power of the earth, his magneticall vertue, according [Page] vnto that forme, and will regularly haue his due points precisely in the ends, without any confusion. Iohannes Baptista-Porta Neapolitanus, writeth that hee did make triall of the way that Paracelsus hath set downe for to increase the vertue of a magnet, namely to heate him red hot in the fire, and to quench him in the oyle of Crocus Martis: And Baptista Porta saith, that hee found it a detestable falshood. For saith hee, he is so farre from increasing his vertue, as that (being once red hot) he looseth all his own, past all recouery. But for all this that hee saith, I doubt whether Paracelsus be iustly reprooued or not, for by mine owne experience I know that the heating of a Loadstone vntill he be red hotte doth weaken a loadstone, but taketh not away all his force, and in my triall here of I found a very manifest proofe of the magnetisme of the earth, which I thought necessary for to insert in this place. I haue made this triall of Fragments of magnets of diuers kindes, and also of diuers kindes of Iron Mines which are next in degree vnto magnets, namely after this sort. Heate him in the fire by little and little (for feare of breaking) vntill he be red hotte, then take him out and let him coole, then marke (with chalke or what you please) those parts that respect the North and South and you shall finde those marked places, the North, and South Poles of the Magnet: put him into the fire againe, vntill he be red hotte, and coole him contrarily, and you shall haue the contrary effect. Therefore if Baptista Porta did make his triall with a Loadstone very long in forme, and chaunced (for Master D. Gilberts mistery of the Earths magnetisme, was not [Page] then reuealed) for to coole him in his oyle of Crocus Martis with his ends East and West, the axis of the stone being then ouerth wart in the middle, it were no maruell if he found no force in the ends. And I do not thinke it improbable, but that Paracelsus way may doe some good rightly vsed. Doctour Gilbert writech that some Iron mine, will affect a magneticall needle, as it is of it selfe, being vnprepared by fire: but as yet I neuer could finde any such, but this I haue often tried, that it being of no manner of magneticall vertue of it selfe no more then a flintstone vnprepared by fire, being made red hott, and cooled, is presently impregnated with very apparant magneticall vertue, according to the scituation that hee is cooled in, and although you heate and coole him often, and diuers waies, he will still keepe his vertue, according to the scituations, of his cooling. And some Iron Mines I haue found, which being but in this sort prepared haue had as strong force as some naturall magnets haue had. It is the goodnesse of the Loadstone ioyned with a fit forme that will shew great force. For as a very good forme with base substance can doe but very litle, so the substance of the Loadstone bee it neuer so excellent, except it haue some conuenient forme, is not auaileable. For example, an excellent loadstone of a pound waight and of a good fashion, being vsed artificially, may take vp foure pounds of Iron; beate it into small pouder, and it shall bee of no force to take vp one ounce of Iron; yea I am very well assured that halfe an ounce of a Loadstone of good fashion, and of like vertue will take vp more then that pound will doe [Page] being beaten into powder. Whence, (to adde this by the way) it appeareth manifestly, that it is a great error of those Phisitions and Surgeons, which to remedy ruptures, doe prescribe vnto their Patients to take the pouder of a Loadstone inwardly, and the small filing of iron mingled in some plaister outwardly: supposing that herein the magneticall drawing should doe great wonders. Whereas they consider not that the stone being dissolued into powder, euery little particle of the dust hath two points contrarie, the one drawing to, the other repelling and putting from: and so being thus confounded by a contrarie working doth much more harme, then good with his magneticall quality. As for the astringent, and drying properties of the Loadstone I leaue them to the diligent obseruation and iudgment of the skilfull in phisicke. But to returne to our purpose, and to alledge this also, besides the former manifest proofe, if the earth were not by nature a magneticall body, the afore mentioned peice of earth could not receiue from a Loadstone any magneticall power: But most certaine it is, and by many vndoubted experiments confirmed, that it will euidently receiue magneticall power, from a Loadstone: therefore it is manifest that the earth is by nature a magneticall body. Furthermore, as among all the mettals iron doth incomparably more resemble the earth in substance then any other doth, it likewise doth more participate with the earth in quality, and principally in the magneticall peculiar property hereof, as notorious experience declareth, yea euery peice of iron Oare, being naturally (as D. Gilbert [Page] sheweth) a magnet, although of feeble force, and all magnets being a kinde of iron Oare, is the very cause, that onely iron or steele, and no other mettall is capable of that vertue, namely to haue that reuiued, and multiplied by the vicinity of a magnet, which at the first in some measure, was originall in it selfe, as it is aforesaid; It is also well knowne, that the magnet is a Stone most commonly of inuincible hardnesse, nothing inferiour to any iron or steele of the excellentest sort, notwithstanding sometimes wee see of them that are nothing, but a dry lumpe of earth, and yet of those also some stronger in vertue, then diuers of the hard stony ones are: Which earthly magnets if a man assay to bring it into a fashion by grinding on a grinding stone (according to the common vse) they will consume into very mudde in the water. Now (to drawe towards an end of this matter) albeit the magneticall vertue be most eminent in the magnet, as in the precise and perfect subiect thereof: yet is the selfe same quality, in a meaner degree, euidently to be discerned in euery peice of earth, prepared and ordered (as is aforesaid) yea although it be not cooled with his ends North and South, that it may take his magneticall force from the vertue of the earth, for if you coole it with his ends but East and West and set two Loadstones in the cooling, the one at one end and the other at the other end, it will receiue a sensible and apparant magneticall vertue according to those points of the Loadstone that were applied vnto it, namely that end which was next the South point of the Loadstone will haue a North properly, and that end that was next the North [Page] point, will haue a South property: yea if you set the North part of two loadstones vnto each end, both ends of this new made magnet will haue a South property; And contrariwise if you apply the South ends of two magnets, both his ends will haue a North property; And those properties before mentioned will shew themselues to be magneticall, because whether end of this new magnet draweth any one end of a magneticall needle, the same will chase away the other: which is proper only vnto magnets, and magnetical bodies. After the like sort, only by application of two strong loadstones by the space of 24. houres you may alter the points of any base loadstone, which you would, and make them both North or South as you please: so that the loadstone which you would alter be but base in qualitie, and not great in substance, and that the other be of a reasonable bignes, and good strength. And this vertue by such application of two loadstones I haue often found effectuall in new bricke lately taken from the kill without any farther putting into the fire at all; And although it be against the nature of a loadstone to haue both his ends naturally of one vertue, that is to say, both of them of a North property, or both of them of a South property: yet here it is to be vnderstood, that it is the forcible violence of the strong ones, being applied iointly vnto each end of the weake, that doe chase the contrarie property of the weake one into the middle thereof: And therefore if you diuide this weak one in the middle, then both those ends, which being ioyned together were the middle, (where no loadstone can shew any vertue) being now disioyned, [Page] and become ends, will presently shew a contrary property (according vnto magneticall nature) vnto the other two ends.

CHAP. II. The ambiguity of the North and South ends of Magnets and Magneticall bodies explained, and Doctor Gilbert therein defended.

THere is not any one errour that breedeth a greater confusion in magneticall knowledge, then the mistaking of the right vnderstanding of the true North and South ends, aswell in magnets themselues, as also in magneticall bodies, who soeuer therefore that will take a little paines in the beginning for to vnderstand this well, shall free himselfe from many intricate difficulties in this argument, which otherwise must needes befall him; wherein some hauing limed themselues, haue fallen into many errors, euery one still begetting another worse then himselfe. All those which did write before Doctor Gilbert did name that end of a magnet which being placed in a wooden dish, and set to swimme in water, would turne and settle it selfe towards the North, the North end of the magnet; and the other the South end. And euen so did they of all Dial-needles, Compasses and magneticall bodies. But Doctour Gilbert, not for any new-fangled innouation, or selfeconceit, but vpon good reason and firme demonstration auoucheth and prooueth the contrarie, and clearely sheweth, that the former vulgar assertion [Page] seriously defended, tendeth vnto the ouerthrow of all magneticall Philosophie, by vndermining (as it were) the whole frame thereof; and yet in common speech the old rule may hold, Loquendum cum vulgo sentiendum cum sapientibus. For it would seeme a strange speech vnto a Marriner to tell him that his Flower de luce were become the South point of his compasse, and yet this assertion is most true, and certaine that it is the North end of euery magnet and magneticall body, that being placed in a thinne wodden dish in water, or any magneticall needle vpon his pinne, which setteth it selfe and pointeth vnto the South, and it is the South end which pointeth vnto the North. For proofe hereof, take these wordes of North and South in whether of the two former significations you please, and make triall thereof in any two magnets, or any two magneticall bodies, so placed that they may freely turne according vnto their natures, and you shall alwaies see a naturall inclination of the contrary ends of the one vnto the contrary ends of the other, as of the North end of the one vnto the South end of the other, and reciprocated of the South of the one to the North of the other; But the ends in the one and the other will alwaies flie from those of like denomination, as the North end of the one from the North end of the other, and the South end of the one from the South end of the other.

For as much then as all magnets themselues, and all magneticall bodies (being so placed as they may haue their free motion) compose themselues magnetically towards the Poles of the earth, it must needs be that [Page] it is the true naturall South end of the Magnet or Magneticall needle, that pointeth towards the North of the Earth: and it is the true naturall North end of the Magnet or Magneticall needle that pointeth towards the South of the Earth, because the contrary ends doe affect one an other, and each of them doe naturally flie, the one end of the one, from that end of the other, which is of like denomination vnto it selfe: for example, In this following Diagram of the whole Magnet, E. A, is supposed to note the true naturall North end thereof, and B. the South end.

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This Magnet being placed in a woodden dish, swimming in water, freely must, and will, of Magneticall necessitie, with his true North end, A. settle himself so, that A. must point towards the South of the Earth. And the South end, B. towards the North [Page] of the Earth: Because all Magnets and all Magneticall bodies, do naturally affect, the one the contrary end of the other, and doe auoide and flie from their ends of like denomination.

Now for a further consideration of these properties suppose that you will cut of a peece of this Magnet meridionally, viz. C. D: manifest experience will shew, that C, which did in nature participate with A. in the entire Magnet, E: (as being both of the true North part thereof) now being separated, will not abide it. In like manner D, of the other end of the little one, will not abide, B: of the great one, with whom being entire in nature he did participate, as being both true Southerly parts of the entire Magnet, E: And that because the ends of like denomination of any two Magnets, doe naturally flie the one from the other.

But here you must beware of an errour, which some vnhappily haue entangled themselues withall: who beholding the afore-mentioned discord (as betweene A: and C:) wrongfully supposed, that, if both these Magnets the greater and the lesse, were conueniently placed to swim in water the little one would not with his end C, point vnto the South of the earth, as it did in the Magnet being entire; where it was a part of the true North end, but would point quite contrarily. There is no manner of any such alteration, but that both the great one and the little one (and all the like, that are cut meridionally one from another) will absolutely point the very same way which the entire one did, only you must know, that the meridian Line will somewhat be remoued [Page] in each of them from the diuision, as you may gesse by the two prieked lines, parallel vnto the meridian (or axis) A: B: of E. the entire one, and the disagreing of their ends is onely within the Orbe of their forces, both their generall dispositions towards the Earth euer continuing one and the selfe-same that it was at the first. Yea moreouer, place them so that they may freely swim within the orbe of their owne force, and they will (with very little helpe or none at all) conforme themselues in such sort that the one of them will ioyne it selfe endlong vnto the other, at their contrary ends, and point the same way both of them, the which they did at the first in the entire one. If you touch the end of any Magneticall needle vpon A, being the true North end of that Magnet, that end of the needle will become a true South end, and will point vnto the North of the Horizon: if you touch it vpon B, that will become a true North end, and will point vnto the South of the Horizon. And the like will it doe, if you touch it vpon, C: as when you touched it vpon, A, and vpon, D, as when you touched it vpon B, although in both these not so strongly; so that Doct: Gilberts assertion doth not gaine-say the Marriners opinion, that his Flower de Luce should not still remaine the North point of his Compasse, onely hee sheweth which end of the Magnet it is, which doth giue him that vertue, namely, that it is the true North end; so that if you hold the true North end of the Magnet neere vnto the Flower de Luce it will come vnto him: if you take away the Magnet, it will come vnto the North of the [Page] Horizon. If you will diuide a Magnet not meridionally as in the former example, but

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aequinoctially, as in this by the pricked line, C: D. A. being still the true North end, and B: the true South end, and A: B: being the Meridian line, or axis of the stone: if you set these diuided seuerall peeces a sunder, that they may swim within the Orbe of their forces, they will affect to ioyne themselues in the very place where they were diuided, as also in the ends, A: vnto B: by the former reasons of contrary denomination. And if you place them a swimming without the Orbe of their forces, A: and B: will still yet retaine their former natures, and euen so will it fall out, if you make your diuision in any other place of the Magnet towards either end parallell vnto aequinoctiall of the Magnet.

CHAP. III. Certaine generall obseruations of the nature and properties of the Loadstone.

LOadstones of diuers and sundry parts of the world as of Norway, Elva, Bengala, &c. haue one and the selfe-same property directiue, I meane of shewing [Page] the North and South, and also the selfe-same points respectiue declining or dipping vnder the Horizon. They doe likewise agree in their variations, and each one will draw yron, and likewise one another. Euery Loadstone, of what forme soeuer he be, hath either actually or potentially two points, the one Northern, the other Southerne. Actually, if either by casualty (if it so fall out) or by industry the stone be so fashioned, that those two opposite points be eminent or perspicuous therein: Potentially, if that either the stone be flat and but thin in the dimension of North and South though broad otherwise, for so shall the vertue of the stone be dispersed to the extreame parts thereof, in the edges round about; or if it haue the two opposite points in any concauitie, then will the stone shew in the eminent border or edge of that concauitie onely a confused dull force, and in the concauitie it selfe very little or nothing at all. That stone is well proportioned for touching which resembleth an Ouall forme, and hath his due points in his ends, and is voide of any bunch or concauitie. For the generall forme of a stone being good, euery concauitie is a diminishing of his force, and euery bunch is but a superfluous burden; Insomuch that my selfe haue made experience of a stone that of substance was very good, and of weight was vpon a three and twenty ounces, but of a disordered forme, I therefore tooke away twelue ounces from him, and yet diminished not one iote of his force. And this did I in a stone that was all of like substance. But if it be one that is intermingled of diuers substances (as many such there are and those [Page] easily discerned by their colour) you may somtimes take away three quarters and more of his substance without diminishing any thing at all of his vertue. For colours, most commonly the Iron-like is best: very blacke or whitish seldome proues good; gray, indifferent; the more white in any stone, so much the worse. There are certaine that are of an yron colour, mingled with red, of which some bee very good, some but indifferent. By three waies you may proue whether a Magnet be good or not; the one is, by taking vp yron with the bare stone: The other by giuing more or lesse vertue vnto a knife, or any such thing to lift yron: The third if it will with good strength moue a Magneticall needle a pretty good distance of, and readily alter the ends of the needle without touching of them, making the North South, and the South North: The two latter of these doe neuer faile, but the first doth diuers times. And very certaine it is, that whatsoeuer stone doth most strongly impart his force vnto a knife, or moue a needle with quicknes, the power of lifting vp yron in such a one, will mightily be increased with a Cap. For this is generally the nature of all Magnets, that if there be 2. of different quantities, and equall strength in lifting vp yron, the greater will giue the stronger touch, and moue a Magneticall needle farther of, although the lesser will take vp as much yron, or somewhat more, than the greater. And againe suppose there be a Magnet of a pound weight, that being fitly armed, will take vp foure pounds of yron, and not aboue, if you diuide him into very small peeces, you shall finde of them being orderly vsed that will lift [Page] vp 20 times, yea 40 times his owne weight and a great deale more, if they be made very small, as of three or foure graines weight; And yet where the great one will giue a touch vnto a knife for to take vp foure ounces of yron, and will moue a Magneticall needle three foote of; this little one will not giue a touch vnto a knife to take vp a needle, nor moue a Magneticall needle foure inches of; that as a Magnet is diminished in substance (I meane a Magnet of a regular forme) so doth he loose in his vertue of touching, and increaseth for his small quantitie in lifting of yron, whereby it is manifest that these two properties goe not alwaies ioyntly together in the same proportion and degree. And here hence it is, that many seeing little Magnets artificially set in rings for to take vp (for their quantitie) a great peece of yron, doe wrongfully imagine that the great one (whose particles they are) or any other great one, should doe the like, namely to take vp so many times their owne weights. Also very often it is seene, that Magnets being of like forme and weight, but of diuers kinds, the one will take vp more yron of himselfe without the capp, and yet the other giue a farre stronger touch; but then, if you doe fit both of them accordingly with caps, he which gaue the stronger touch, will take vp more yron than the other. The principall force of the Loadstone well proportioned, passeth in a direct line, from the middle of his substance, being (as it were) a Center, through his two ends or points, which are the imaginarie lines of his chiefest force, from which Center, there issue infinite others also through all parts of the Superficies of the stone, [Page] on either side, betweene the two extreame points and the middle, all which on either side of the middle, being of one nature and property in respect of their touch are exceedingly different in strength. For that still waxeth lesse and lesse, as it approacheth continually nearer and nearer the middle, where at length in the middle, betweene the two ends, it vtterly fainteth and commeth to nothing. The Loadstone communicateth his property to the yron or steele that is touched with it, so farre forth, as the yron, or steele, which is touched, hath habilitie to receiue, and so that good skill in the touching be obserued, steele is farre better than yron, and receiueth a farre stronger touch, and much more effectuall. The purer steele, so much the better; and if it bee yron, the purer likewise, the better, alwaies regarding that both of them be very smooth, and cleane, and haue their due temper. The principall property in common vse is the shewing of North and South in the Horizon, with the appendants therevnto belonging, which is much more apparant, more strong, and more commodious in the iron and steele, that is touched, than it is in the stone it selfe, because the substance of them may be filed and cut away, and drawne into any forme, that we like or list our selues, which the substance of the stone will not permit. The Magnet is of such nature, that euery peece broken of and separated from the whole, hath all the properties of the whole, the same seuerall points of North and South, and habilitie also for the touch, like in kinde, though not of equall power, according to the quantitie and proportion of the peece, and the [Page] part of the stone that it is taken from, and this propertie in a meaner sort hath the touched needle and wyar of a Compasse also.

CHAP. IIII. By what meanes the chiefe points of any Magnet of what forme soeuer may easily be found out.

MAke a respectiue or declinatorie needle, of an inch or thereabouts in length and giuing him his touch, fasten him by his Axis vpon a little forked sticke, or any such thing, that the needle may haue free scope, then offer the stone neere the needle, turning it round about, and immediately you shall see the North of the needle (as it is as yet commonly called, because it pointeth vnto the North) point directly vnto the true North end of the stone as soon as it commeth neere vnto it, and as you turne away the end of the stone the needle will point still somewhat towards it, till the South end of the stone approacheth, for then will the needle wheele about vpon his Axis, and point directly with his South, and to the true South of the stone. But if you hold the needle neere the stone, in such sort that it cannot turne about at liberty then the force of the stone may soone change the properties of the ends of the needle, that the one point which was North shall become South, and that the other which was South shall become North, yet the thing it selfe is easily discerned: For the Northerly end will alwaies hang lower.

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[figure]

And wheresoeuer the needle, being held neerer vnto the stone doth stand parrallell vnto it not inclining with either end, towards the stone there directly, vnder the middle of the needle, the North and South properties of the stone doe diuide and part themselues. This matter is much better performed, with a smal narrow loadstone of halfe an inch (more or lesse) in length, hauing in the ends his due points of North and South and wrought ouer with silke of two colours from the midle to each end; as for example yellow and white; That part which pointeth to the North let it be wrought ouer with white, and the other with yellow. Then if you hang that in the midle by a fine silke thread, and apply it vnto any other loadstone, the South end of the one will readily finde out the North end of the other; and contrariwise. In like manner, with this magneticall instrument you may see two pretty conclusions. The one if you touch a knife with the end of a forcible loadstone, whether it be North or South, and hang this wrought one by a silke thread in the midle, that [Page] it may hang freely, the one end will craue towardes the point of the knife, and the other will not abide it. The other is, if you hang it end-long, with the true North end right ouer the North end of a forcible loadstone or with the South end ouer the South end of the other, you shall see that it will in no wise (being let downe) come vnto the North point of that loadstone, but will (contrary to philosophicall principles that heauie things should tend directly downewards) by the meanes of the silke thread, swimme or wheele about the end of the loadstone in the aire: yea and lift it selfe somewhat vpward, rather then perpendicularly light downe vpon it, yea this it will do although you place a plate of siluer, lattin, or any such thing, betweene the stone and it selfe.

The second way.

Thread a common sowing needle, and touch the point of it with the North end of any loadstone, then offer it vnto that stone whose points you would find out, holding the needle by the thread about an inch there-from, and in turning the stone about, you shall presently see the needle point vnto the North end of this stone, and flie from the other end, when by your turning it commeth neere. The contrary effect ensueth, if you touch the point of the Needle with the other end of the stone, wherein you may behold that ancient conceiued, and of late yeeres maintained errour of the contrarietie of Magnes and Theamedes to be nothing else but a contrarie property of one and the selfe same Magnes.

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The third way.

Breake off the point of a sowing needle, halfe an inch long or longer (if the stone be good) but not aboue a quarter of an inch, (if it be a base stone) lay it vpon the stone, and moue it to and fro vpon the Superficies thereof (being smooth) with the needles point forwards, and as it commeth neere any of the two points of force, it will raise it selfe more and more: but being brought vnto the point it selfe, it will stand there straight vpright; If the stone be ragged this cannot well be practised, otherwise of all other it is the most certaine way. Now whether it be your North or South end the effect will soone declare.

The fourth way.

Hauing an ordinarie Diall with a magneticall needle, or a sayling compasse, or any magneticall needle standing on a sharpe pinne, hold neere thereunto the stone turning it in your hand, then will the north end of the needle (I meane the end that pointeth to the North) respect the true North point of the stone.

The fift way.

Also if you touch a common sowing needle (the longer the better) and put ti through a little peice of corke, not bigger then may well beare it vp, so that by the meanes thereof, it may swimme in a bason of water, the same if you offer the stone vnto it, will [Page] shew the like effect. And here it is to be remembred, that none other way whatsoeuer will more readily or truely define the magneticall Meridian, then this of the needle with corcke in the water. And therefore as it is very requisite for many purposes that euery Traueller either by land or especially by sea should alwaies haue (if he may) an aequinoctiall Diall with him, so would I not wish that any of them should be without some sowing needles touched with a good stone which wil both serue the proper vses of sowing without impairing their touch (for it is open aire and rust that are the greatest enemies thereof) And at any time with a peice of corcke, or a drie sticke in the water will shew the magneticall meridian; a matter though meane and triuiall in shew, yet betweene whiles of so great importance that it may serue to saue very many mens liues.

A sixth way.

Also if you prepare a little round Loadstone of a quarter of an inch diameter or there about (but it must be a very good one) hauing his two poles marked and fitted in such manner that it easily turne about in a little frame according vnto this picture. The like also in his sort will come to passe, if you hang a small declinatorie Needle in a frame in this manner.

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[figure]

Then by mouing it in his frame all ouer the stone, the North pole of this will finde the South of the other; And likewise will the South, the North of the great one; For it is not in outward shew between one magnet and another, as it is betweene a magnet and a magneticall needle, the contrarie ends of the magnet will couet in their motion to meete together, but the end of the needle which turneth North, will come vnto the North of the stone: For in very truth it is the South point of the needle, euen as the magnet it selfe being placed in a woodden dish in water will turne with his North end vnto the South, and with his South end, dish and all, towards the North, as it is largely declared in the second Chapter of this booke. The like effect will also follow if you hang as aforesaid a small magnet in the middle by a small silke thread, that it may freely turne without impediment according vnto his owne nature. But this property it will shew quicker, or slower according vnto the goodnesse of the substance, and fitnesse of the forme. The best forme for this purpose is the extended ovall, hauing his poles precisely in his ends. If his poles be some pretty distance, the one end towards [Page] the East of the stone, and the other asmuch towards the West, this stone in his length will not point vnto the magneticall North and South (as otherwise he would) but vnto some other point of the Horizon; yea following this experiment in this sort, you may make him stand vnto any point of the Compasse: onely you ought to abridge the stone in his length that he may come somewhat neerer vnto a circuler forme, that so his diameter of North and South (being through the magnetisme of the earth, the cause of this motion) may be so much the longer in comparison of the Masse of the stone, and consequently more effectuall. After the like manner you may so touch the wiers of a Compasse, that the Flower de luce of the flie, shall stand vnto what point of the Horizon you please, although the Diameter of the wiers doe still remaine fixed vnder the Flower de luce, and the South point of the Carde.

Finally to conclude this point with a magneticall delight, if you touch two sowing needles in a contrary sort, that is, the point of the one northerly and of the other Southerly, and set them with their corckes the one at the one side of a bason of water and the other at the other, you shall see them, as quickned with vitall spirit, euen so to moue the one end towards the other, at the first faire and softly, but when they draw neere they will rush together (as it were) with a kinde of violence, the point of the one striking precisely at the point of the other, you must place the needle, whose point is touched for the North on the South side of of the bason, and the other on the other side: Otherwise the heads [Page] and not the points will runne together, a thing farre more worthy of admiration, then all the selfe moouers of any Daedalus or Architas Tarentinus, and more strange to behold then the connexion of Iron rings combined by vertue magneticall, whereat S. Augustine so much, and that iustly, did wonder.

CHAP. V. The manner of capping both with single and double cappes and the nature of them.

THe stone being brought vnto his perfect forme you must haue a mould made of Iron of the very same proportion in euery respect and equall in all his dimensions, then setting the stone aside, let your workeman frame & fashion his cappes and fit them vpon this mould as if it were the stone, thus shall you be sure to preserue your magnet from many dangers, very incident vnto rude handling: And hauing so done you may set them on the stone it selfe, amending any small faults, without endangering the stone, either with bruisings, or knocks; For the thicknesse and largenesse of the cappes, there can bee no generall rule prescribed, but it must be left vnto the triall and ingenious dexterity of the workeman: as also for the handsome fastening either by soadering, or riuetting of them with lattin plates to the Caps to keepe them in their places firme and steddy, according as you see in this picture of a stone, armed with single Cappes.

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[figure]

The double Cappes are nothing but two square or round knobs prominent and issuing out of the single Cappes (as neere as may be) at right angles with the Axis of the stone, agreeable to this forme, which was fashioned by a very skilfull workman

[figure]

of Winchester, one that for all manner fashioning, cutting, soadering, peecing, and capping of Loadstones, is the most exquisite that I haue knowne, as Doctor Gilbert would also confesse, who had his best fashioned and capped by him; and so some Noblemen and diuers Gentlemen, to their great contentment, haue had the like. I finde not as yet any profitable vse of the double capping, but only for admiration, in taking vp a greater quantitie, more by the one [Page] halfe, then the two seuerall ends could doe each by it selfe: as if each end will take vp halfe a pound, being capped in this sort, that each prominent end may lay hold vpon the iron fitted for it in this maner,

[figure]

it ought to take vp a pound and a halfe and more: The reason whereof is this, because the Magnet, in touching any one end of a fitting peece of iron or steele, doth not onely infuse the vertue of that end, which toucheth the iron, into that touched end, but also the contrary vertue into the other end.

Now therefore in this position, both ends of the Magnet being applied vnto the two ends of the iron, [Page] these two contrary forces striue in this peece of iron, the North to repell the South, and the South the North: so that each force is driuen neerer his owne end, and becommeth there so much the stronger then otherwise it would be. For proofe whereof, take a little narrow square peece of iron, of the length of the capped stone, and ioyned in the middest with Copper after this sort:

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A. is supposed to be a long square, or a square-like peece of iron, in length fitting the two double caps of a Loadstone.

B. a long square peece, the ends iron, the middle copper. C. hath a lesse space of copper, and D. least of all.

If you apply the Loadstone vnto A, he will hold A very strongly; but if you put any of the other three peeces vnder A, that it may touch any of them, hee will not by any meanes lift it vp. If you apply the Loadstone vnto B, he will take it vp very weakly, and C somewhat more strongly, but D strongest of all these three, yet not comparable to the strength [Page] wherewith hee taketh vp A. Againe, although the Loadstone taketh vp B but weakly, yet if you place B vpon A, he will take them both very strongly; yea more, place B vpon C, these two vpon D, all three vpon A, apply the Loadstone vnto B, being the vppermost, and he will lift them all vp very easily.

The cause hereof is, when a Loadstone with his double cappe is placed vpon A, the force of both ends striuing in that peece of iron paralel-wise vnto the Axis of the stone, the North and South forces are driuen more closely vnto their proper ends. But in B, (because of the intermediate copper) there can be no such close driuing of his forces into their proper ends, as was in A: and therefore the Loadstone lifteth vp B, but only as if his two ends were two little loose peeces of iron, hanging in the aire, and the intermediate copper a burthen vpon them. But placing B vpon A, A in the manner (as it were) of a bridge, ioyneth the two ends together into their former combats, and the two ends of B, forasmuch as they are but (as it were) two loose peeces of iron hanging in the aire, the two forces of the Loadstone North and South, distinctly and seuerally passe thorow them downwards into A, which it could not doe, if it had beene one entire peece of iron: and so all those foure peeces, being placed one vpon another, so that A be vndermost, whether directly or sidewise, the Loadstone will easily lift them all vp, and not otherwise.

When a Loadstone lifteth vp iron at one end onely, the vertue of the stone is infused into the whole body downward of that iron, if it be not very long.

[Page]But when by the meanes of the double cappes, both ends doe lift iron ioyntly together, he infuseth very small force downeward into the body of the iron that it lifteth vp for the forces of the both ends are so striuing in a collaterall line of the iron, paralell vnto the Axis of the stone, that whereas a good Magnet lifting vp at one end, will extend his vertue downewards twelue or fourteene inches, in applying both ends vnto the iron, by the meanes of the double caps, hee will not extend his force downeward the distance of one inch, nor with any strength the distance of halfe an inch, as in this former example.

If a Magnet will lift at one end a pound of iron, fasten you halfe an ounce of iron vnto foure ounces of wood, or any other substance sauing iron, and he will neuer take it vp, because his vertue can pierce but onely that halfe ounce, and hath no power to enter into the other substance; and that small portion of vertue, contained in the halfe ounce, cannot hold vp the other strange substance. But this very same Magnet, by the meanes of double caps laying hold of a peece of iron fitted for the purpose, and of this fashion, being but halfe an ounce, may very well and [Page]

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readily take vp three pounds of any other substance whatsoeuer that is fastened vnto it, because that the whole force of the stone being imployed in the strife of the contrary ends, in the iron paralell-wise, vnto the Axis of the stone, each end apprehendeth and lifteth vp this peece of iron and a great portion of any other substance that is fastened vnto it, and his whole force being imployed herein, all his former vigour, vpward, downeward, or endlong, is as it were fettered and imprisoned, that vntill you loose him of these fetters, hee is not able at either end to take vp one quarter of that which he did before.

Pliny in his naturall historie writeth, that Dinocrates that famous Architect builder of Alexandria, at Ptolemies commandement began to vault a Temple with Magnets, that there might seeme to hang in the aire the image of his sister Arsinoe, made of iron [Page] for that purpose: but both Dinocrates and Ptolemie dying in the meane space, that enterprise ceased. Neither indeed (if they both had liued) could it euer haue come to passe by that means, by reason of two impossibilities: The one is, that by the force of the Loadstones, nothing can so hang in the aire, but that it either must touch the stone it selfe, or some other intermediate substance betweene it and the stone, that barreth it from comming to the stone it selfe. For example, lay two or three needles vpon a smooth table, put a siluer or pewter plate vpon them, and vpon the plate a Loadstone, then lift vp the plate aloft with the Loadstone lying still vpon it, and you shall see the needles hanging indeed in the aire endlong, and if you moue the stone about the plate, following still vnderneath, but euermore touching the plate, which is the intermediate body, that keepeth them from comming to touch the stone, which otherwise by their naturall inclination very speedily they would doe. But as for that image of Arsinoe; how had it beene possible for it to haue touched at once, mediately or immediately, so great a number of Magnets, whereof the pretended vault must needs haue consisted? The other is, that such a multitude of Magnets would nothing but confound the one the others forces, so that one of them alone being solitarie and seuered from his company, might shew more force then al that insociable societie could doe, each one hindering the efficacie of the other. Much like a teeme of many horses, where euery one drawing his sundry way, might soone with disordered stretching tire himselfe and his fellowes, but neuer [Page] moue the loade one iot from the place. Insomuch as one (and possibly the worst) would doe more good alone, where hee might orderly and freely vse his owne strength, then hee and all the many of them could doe being ioyned together in vicinitie of bodies, but extremely distracted through contrarietie of courses.

The only way to performe such a matter (if it were worth a doing) would be to prepare one mightie great Loadstone of excellent goodnesse: which hauing his due proportion, after an extended ouall forme, should be sitted with double cappes, and so placed in the roofe of a building, that his Axis be paralell to the Horizon: in this sort (out of all doubt) a faire large image might bee held vp very strongly by such a Magnet, let the stuffe or substance thereof be whatsoeuer, (howbeit the lighter the better) so that there be fastened vnto the vppermost part of the Image a small peece of iron accordingly prepared and placed for the two prominent ends of the double cappes of the stone, to lay hold thereon. But enough hereof.

In the capping of Magnets, this generall rule is to be obserued, that they ought to be made of the finest and softest iron, and not of steele: the waight also, which the Magnet taketh vp, should be of the like iron, and not of steele, as aforesaid. For although steele retaineth at the least ten times as much vertue as iron, when it is once separated from the stone, can doe; yet as long as there is any contiguitie betweene the stone and them, hee holdeth iron more strongly then steele. Both which differences in either of them [Page] by manifest experience are certaine, and seeme to proceede of notable fastnesse or closenesse in the steele aboue the iron; by meanes whereof the magneticall vertue doth longer and more forcibly continue in that then in this: euen as fire more mightily possesseth, and for a greater space abideth in stone, or any such firme or solid matter, then in wood, or straw, or the like thinne and hollow substances: and therefore those compasse-makers, that make the wiers of their flies for sailing compasses of meere iron, ought not by any meanes to be suffered: for to gaine two pence in a compasse (and scarcely that) they intollerably abuse those that trauell by sea, to their great danger and mischiefe.

CHAP. VI. Of cementing and peecing of Loadstones.

FOr your Simmon, doe thus: Take the fine powder of a Loadstone, halfe so much powder of new bricke made very small and subtill, one part of Burgundie pitch, halfe so much Rossen, a small portion of vnwrought waxe: mingle all these together very well vpon a soft fire, and make the whole masse in little roules. Now when you will cement a stone, doe thus: heat the two peeces of the stone very hot, and likewise the simmon, then strake the places that you will soder, ouer with the simmon very thinly, and ioyne them somewhat hard together, letting them so stand vntill they be cold, and you [Page] shall haue it fully as strong, as if it were an entire stone of it selfe, and not to be seuered but by great heat of fire. In peecing of the Loadstones, there must diligent heede be taken to the nature of the Loadstone in generall, and also to those particular peeces which you would ioyne together. The Loadstone in generall (as it is shewed before) that his force issueth (as it were) from a center in the middle of the stone, to all the superficies thereof vniuersally, but most strongly vnto the Poles from the middle, one way the stone is all of a Northerly nature, and all of it Southerly the other way. For example.

[figure]

A. is the North end, B. the South end of a Loadstone, D. the middle. Suppose you cut off a peece at C, then shall D. be no more the middle, but it shall be a part of the North of the stone, and the middle is remoued neerer B, and the vertue of North and South doth not now diuide it selfe at D (as it did before) but D. is now become a part of the North end of the stone, which it was not before. In this example following let there [Page]

[figure]

be two Loadstones, the one longer then the other, the North of both noted with A, the South with B, the middle of the shorter, where the North and South properties doe part, is C. Suppose you will fasten these two with simmon, the end B. of the shorter vnto the end A. of the longer, so shall these two become one Loadstone, and not onely C, which was the middle (where

[figure]

the North and South properties did part) in the little one, is now become a part of the North end in this conioyned Loadstone, but also euen B. it selfe, which was in the short one the very South Pole, is now in this become part of the North portion, the middle of this (where the North and South properties [Page] doe part) being in E, and these two Magnets, which had each of them two points, the one North and the other South, being ioyned together, haue but only two points in all, the one North, the other South. Moreouer, if you haue two Loadstones (for example) of like goodnesse, about foure inches a peece in length, hauing their North and South points duly at their ends, if you cut off at either of their ends halfe an inch, and conioyne them with the contrary of the great ones, they will presently haue contrary properties vnto that which they had before; so that a needle touched before that would turne North, being now touched in the selfe same place will turne South, shewing that the vertue of the two ends doth alwayes proceed and extend it selfe from the body of the whole Loadstone, and from the whole, sheweth it selfe most forcible (as aforesaid) in the ends; and either of the Loadstones will be in his perfect goodnesse, as at the first. If you thinke good to set two Loadstones together in such sort, that you would haue the augmentation onely in thicknesse, and not in length, then doe thus: If they be both of one length, grinde them so that they may ioyne close, the broad side of the one agreeing with the broad side of the other, hauing North vpon North, and South vpon South, as in this example.

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[figure]

A. must be ioyned vpon A, and B. vpon B: but if you ioyne the two so, that A. lighteth vpon B, you marre the new Magnet, by confounding his forces. Notwithstanding if you like to ioyne them in length onely, not in thicknesse, then indeed must you combine B. and A, and not A. and A, nor B. and B, lest here also you incurre the former inconuenience, of confusion of forces. Take another example: Suppose a Loadstone to bee long and somewhat round, smaller at one end then at the other, the smaller end to be North signed with A, the other South signed with B: let this Magnet bee diuided long-wayes into two equall parts, thorow both the Poles, A. and B.

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And let one of these halfes be placed vpon a peece of glasse or a smooth Table; certaine it is, that if you do offer to touch A, of this, with A, of the other, this A will turne away from that, which (the stone being entire) it did ioyne with before: Or if you offer B, vnto B, it will doe the like. And no maruaile, for in this case of touching A, with A, or B, with B: what else in effect doe you, but attempt to ioyne the two halfes in length and that at like ends? A thing directly repugnant to the principles of Magneticall Philosophie. But let me admonish you, to put the rounder side of the stone downewards, next vnto the glasse, that it may turne the quicker: yet if the stone be excellent it will doe the same also vpon the flat side. Moreouer if you place this two halfes, the one vpon the other precisely as they were at the first, they will [Page] agree very well: because they are as one, and the selfe-same Magnet. But if you place them the one swaruing from the other, at either end, then will A, of the one, turne about vnto B, of the other; because they are now as two seuerall and diuers Magnets. For the better conceiuing hereof, you are to remember, that euery part of a Loadstone (be it an half or any other) being once diuided from the whole, is (as Schoole-men call it) Totum integrale, a whole Loadstone by it selfe, vtterly diuerse and estranged from that whole, whose part before it was, and therefore reteineth distinctly in it selfe, all the properties of a Loadstone, though not so strong, as the whole had when this was ioyned therevnto.

In Loadstones there is a part truely said to be diuided from the whole, when the points of that part, or ends, or Poles (and so, by necessary consequence, the Axis and Aequator, in which the vniuersall frame of Magneticall power consisteth, haue a position diuers from the Poles or points of the whole. For this cause, in the last example the one halfe A: B: being supposed to swarue from the other halfe B: A: at either end, must needs presently be diuided from it, and now cannot be pars integri, but is of necessitie Totum integrale, a seuerall and absolute Magnet of it selfe, and so by an essentiall property common to all Magnets, coueteth with his point A, the contrary B: of that which is vnder it. Wherefore like as exact agreement is betweene two Mathematicall figures when being applied together, the extreames of the one, doe precisely fall vpon the extreames of the other, each vpon his correspondent extreame, and [Page] is made one therewith: euen such is the perfect composition or setting together of the parts of a Magneticall body, and namely of those two equall parts before exemplified, you must so ioyne one vpon another, that the two extreames, or ends, be alwaies of the same nature Northerly, or Southerly, in both parts: And that by due application of the parts, the two Northerly ends be vnited, and become one, as also the two Southerly ends after the same manner. But if these parts, being of equall length be ioyned longwise, the North of the one, vnto the South of the other; those two ends that were (being now no ends but the iust middle of one Magnet) haue lost their properties which they had, when they were ends. For those properties, by this vnition, are abolished: but their other ends still reserue their former and stronger vertues of North and South: And so, according vnto Magneticall nature, one Magnet shall haue but two Poles, the one North, the other South. Againe, if you will peece two Loadstones together in thicknes, the one of thē being longer, than the other; then you must either cut the longer, that it may be fit in length, vnto the shorter; or else peece the shorter in such sort as is afore described that he be equall in length to the longer, & what soeuer disorderly parts perhaps shall bee in any of them, they may, euen after they are cemented, very well be ground away. Also if there bee holes or dents, with little peeces of Loadstones cemented (their points being obserued) they may be filled vp, without any manner of dammage or deformitie, no more than there had not been any such at all. And [Page] after this method you may (with labour and industry) of many Magnets, make one as huge, and of what forme you please. And although the Magnets of this body, magnetically compact (as I haue here shewed) were neuer so many in number, yet the whole will haue but two principall points, the one North, the other South, euen as if it were one naturall Loadstone: and all of them will contribute their forces, vnto those two points; So that if there were twenty of them, being after this order cemented together into one body, the whole would haue but two points, but if you will place them in a vault, according to a Masons trade they will haue 40 points, twenty North, and as many South, and will worke the like effect in drawing yron, as (to vse the former grosse similitude) if a teeme of horses were set in their traces contrary the one to the other, the one to pull one way, the other another. As for the Turkes Mahomet, hanging in the ayer with his yron chest it is a most grosse vntruth, and vtterly impossible is it for any thing so to hange in the ayer by any Magneticall power, but that either it must touch the stone it selfe, or else some intermediate body, that hindreth it from comming to the stone (like as before I haue shewed) or else some stay below to keepe it from ascending, as some small wier that may scantly bee seene or perceiued.

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CHAP. VII. Of the variation of the Magneticall Needle with the Appurtenances therevnto belonging.

THE variation of the Magneticall Needle, being aptly fitted and placed vpon his pinne, is nothing else, but the swaruing of the pointing thereof in the Horizon, from the meridian line there, the portion of the Horizon intercepted betweene the true Meridian line and this pointing, sheweth of what quantitie the variation is, and giueth it his name, to wit, which way it lyeth, either Easterly, or Westerly, and it is obserued by either end of the needle as you please.

In times past men obserued onely by the North end of the needle, because they vnderstood not that the Loadstone hath a South vertue, as well as a North; And therefore did touch their needles and wyars of their compasses alwaies for the North onely, leauing those ends of the wyars bare, that they might be refreshed with a new touch at any time afterwards: but the other ends they couered, not knowing that they were also apt to receiue as forcible a vertue from the Loadstone for the South, as the other for the North. For the right vnderstanding of the variation, with his necessary dependants, wee must vse the meanes of two circles: The one of them I will call the Magneticall Almicanter; The other is already knowne by the name of the Magneticall Meridian.

This Magneticall Almicanter is a circle paralell vnto [Page] the Horizon, whose center is the verticall point, and is described by the distance betweene the verticall point, and the neerer Pole of the earth. The true Magneticall Pole is the pole of the earth; The magneticall respectiue Pole, or (which is all one) the Pole of the Magneticall Meridian, is a point in the Magneticall almicanter, distant Easterly or Westerly from the true pole as many degrees in that almicanter, as the variation of that place containeth in the Horizon, but alwaies it is in the contrary part of the true Meridian, that is, if the variation of the South point of the needle be Easterly the respectiue pole is Westerly: but if you obserue with the North end of the needle, the respectiue pole and the variation are both one way in all our Northerne Climates. If the variation of the South point of the needle bee Westerly, then is the respectiue pole so many degrees in the said almicanter Easterly, and therefore alwaies of the same height with the true pole aboue the Horizon. For since all great Circles of the globe doe necessarily cut one another in two points into two equall parts: these two therefore must needes doe euen so in the Zenith and Nadir, by their very definitions; So that these two points (the Zenith and Nadir) are alwaies alike common vnto them both, aswell vnto the true, as vnto the Magneticall Meridian.

Where-hence it followeth necessarily, that alwaies the one halfe of the magneticall meridian is on the East-side, and the other on the West side of the true meridian, the common Zenith and Nadir euermore keeping their equall distances from the Poles▪ [Page] of the one of them, as they doe from the other. For example: Suppose the common Zenith to be in the Aequator, you sayling East or West, as long as there is no variation, there is no magneticall meridian, there are no magneticall Poles, but those of the world. But as soone as, sayling still vnder the line you doe finde a variation it is the magneticall meridian, that by his swaruing from the true meridian of the world in the Horizon sheweth the quantity of the variation, and giueth it also the denomination of Easterly or Westerly, and his axis is the line of variation. But supposing the common Zenith, to be in any paralel, betweene the Aequator and the Pole, then is it not the axis, but some other Diameter of the magneticall meridian, which sheweth the variation in the Horizon; And the magneticall meridian euermore cutteth iust so many degrees of the magneticall almicanter on the one side of the true meridian, as the same Magneticall Pole is distant in the same almicanter, on the other side of the true Meridian from the Pole of the World. And this is to be vnderstood in correspondent manner, as well of the South Hemisphere, as of the North.

The respectiue Magneticall meridian (where any variation is) is a circle that passeth by the verticall point and the Nadir, and both the respectiue Poles, crossing the Horizon at right angles in the points of variation, of which circle the line of variation is a Diameter, but where there is no variation the true and Magneticall meridian are both one & the selfe same, and so in like manner are their Diameters. Those circles and poles are tearmed respectiue because that in [Page] euery place where any variation is, the Magneticall needle doth respect them, as well in the property of direction, as in that of declination, or inclination. For thus also very well it may bee tearmed. By the property of direction, I doe meane, with Doctour Gilbert, the Horizontall motion of the Magneticall needle: By the declination, or inclination, I meane the descending, and (as it were) the sinking motion of the neede vnder the Horizon, in his proper Azimath, or Magneticall meridian; But if there be no variation, the needle alwaies pointeth vnto the true Meridian of the earth, and towards the Poles therof, in both those properties. The true Poles of the earth (which are those two points equally distant from each part of the Aequinoctiall of the earth are alwaies the selfe same. The respectiue Poles alter with euery Horizon, where there is any variation, but neuer out of the aforenamed almicanter of that place. The causes of the differences of the respectiue Poles and Meridians from the true Poles and meridians, and so of all variations, are onely two; The chiefe and most generall is the vastenesse of the Ocean sea, by moistnesse whereof the Magneticall collaterall force of so much earth as it couereth, is much hindered and dulled. And by that meanes the next great Continent hath more power ouer the correspondent end of the Magneticall needle, then otherwise it could haue if all were alike one entire Continent: and therefore causeth the directiue property of the needle somewhat to swarue towards that way, which is that, which we call variation; but yet the vastenesse of the Ocean doth not hinder the declination [Page] of the Magneticall needle; Because his hangings consisteth but in length and breadth, and not in depth. For although in comparison of a pond or riuer, the sea is said to be of a wonderfull depth, yet if this depth be compared with a Semidiameter of the earth, it beareth a very exceeding small proportion, nothing at all to hinder the mightie magneticall declinatory force of the whole earth; For the greatest depth that euer any man of skill esteemed it at, was not aboue two English mile, at the vttermost, when as daily experience maketh it manifest, that a great Continent wil shew his Magneticall collaterall force, by causing a variation, aboue two hundred miles of from the place, and therefore Doctor Gilberts feare in that point I take to be needlesse, supposing a variation of declination. The second cause of variation, is any great mountainous region not farre of, when a man is in some great Latitude towards either of the Poles: if that mountainous region lie Easterly or Westerly from you, it will cause the needle somewhat to swarue that way. But variations of this sort are of small continuance, and in sayling subiect vnto sudaine alterations, yea many times quite contrary from Westerly to Easterly & afterwards backe againe within short space: as our first famous Pilote Steuen Burrough found by his experience in the discouery of the Scythian sea-coast between the north Cape of Finmarke and Vaygates. The reason whereof ought heedfully to be regarded which is that the Magneticall force of the whole earth, doth (as in all Magnets) shew it selfe most strongely in the two Poles thereof, and in those places which are neere vnto [Page] them: but alwayes it must be remembred, that all the force they haue doth issue out of the whole terrestriall body, as it doth likewise in all Magnets out of the body of the Magnet: and therefore in any part of the superficies of the whole terrestriall body, it is impossible that any variation be aboue 90. degrees, because the vertue of the whole can neuer bee ouerswaied by the imperfection of a part, and especially of so small a part as any one portion of the Ocean is in his very superficies, in respect of the body of the whole earth: yea I am thorowly perswaded, that there neuer was nor euer will bee any variation, by any good obseruation found for to bee so much as ninety; neither any shew of so great variation any where, except it bee very neere vnto either of the Poles, where there is small credit to be giuen to the obseruing of any variation: for the variation being (as aforesaid) the difference of the pointing of the magneticall Needle in the Horizon from the true Meridian, for asmuch as in places neere the Pole, there is no manner of certaintie of either of these, it is not possible to finde the variation, if there be any. The reason whereof is this, no man may trauell those Seas, but whiles the Sunne abideth on that side of the Aequator, whereby they haue continuall day, and by that meanes are secluded from any helpe of the starres, neither if they might bee seene, would they bring any great helpe. For the difference of heighth in many houres is so small, that by a very large instrument a diligent obseruer with great paines will hardly finde the Meridian Line, all the Meridians themselues comming [Page] so neere one to another, and meeting in the Pole, and their Horizon being in a manner paralell vnto the Aequinoctiall. And as for the horizontall magneticall Needles, to shew their pointing in the Horizon as they were wont to doe, they comming into this climate may say, Fuimus Troes. Their direction is as it were giddy and vncertaine, and when their center commeth vnto the Pole it selfe, it is quite vanished away; for from thence all the points of the Horizon are onely South, if it be at the North Pole, and North from the South Pole, and therefore in that place the instrument of declination is farre more sure then the Horizontall Compasse. And as in the Poles themselues there is no direction at all, so of necessitie neere vnto them it must bee a very confused direction. Those two places, that are called the Poles, haue no strength of themselues (as aforesaid) but as it is contributed vnto them of the whole. As in a Magnet, if you breake off a peece of the contrary end, the end that is left will bee according vnto that proportion diminished in his strength, and the polar peece, that was broken off (be it neuer so little) will haue two poles as well as the great: so that the two parts will haue foure Poles, two of them North, and two South. Put this little peece that was broken off, in his place againe, and then each peece will lose one of his Poles in the same very instant, and the whole will haue but two Poles, the one North, the other South, as at the first. Againe, if you cut off a peece of one side of a Loadstone, that is brought into a round or an ovall forme, hauing his Poles marked in their due places [Page] at each end, presently both end will be abridged of part of the force they had, and the Poles themselues will be remoued vnto the other side, from the places that were marked, and those markes will stand but for idle ciphers in comparison of that they were before. Againe, take a Magnet of a round or an extended ovall forme, (I doe still exemplifie in these, because they are of all others, as I haue often admonished, for all magneticall proofes the most excellent formes) and set markes on the two Poles, take a fine needle, or any straight small wier, and set it on the aequinoctiall, (I meane thereby the middle betweene the two ends of the stone) then will it point directly towards each Pole, if the stone bee sound without any flawes, or any other grosse substance (as may bee) intermingled with it: and if you thrust this needle towards either end, according vnto his owne direction he will trace you a circle right ouer both of these marked Poles, which is the true Meridian of the stone. But if this stone hath in either of the sides any imperfection, when the needle commeth vnto the edge or brinke thereof, it will swarue somewhat towards the sounder side, and will point to neither of the true Poles. And if a circle bee drawne according to his pointing, as hee standeth still in that place, this shall be a respectiue Meridian of that stone, proper vnto that place: and the Poles. the respectiue Poles, differing from the true Meridian of the stone and his Poles. Now if you thrust the needle further towards the end, vpon the brinke of this imperfection, it will not point (as before) but either further off, or neerer towards the true Poles▪ [Page] and will giue his direction for a new respectiue Meridian; and new respectiue Poles, And in such manner infinitely, if you place the needle in the middle of this imperfection, equally distant from the sound parts, then will it indeede poynt towards the true Poles of the stone, And the Consequence heereof is the maine reason, that towards the midst of the Ocean; and likewise of any great continent there is no variation. Thus may you especially in a round Loadstone (as in a liuely example) see the true causes of all the variations that are in the whole world, reckoning as much space as the Ocean couereth, to bee some imperfection in the body of the whole, in respect of the Horizontall motion of the Compasse. For the euidence of the truth heereof, let a man examine generally the variations of our most expert Nauigators (Although by reason of their diuersities of the sets of their Compasses, and vnfitnesse and vnapt handling of their instruments, they very seldome times agree among themselues) obserued in the Atlanticke Ocean, from the Aequator vnto the parts of Norway, all along the East coast from the Meridian of the Azores: And in like manner from the Aequator to the parts of New-found-land and vpwards, all along the Westerne Coast from the Azores, as farre North, as heereunto hath beene discouered, and he shall finde the ordinary practise to testifie the truth heereof, as also after the same sort from the Aequator Southward vnto the straights of Magellan, and all along the backeside of America in the South Sea: and on the East Coast vnto the Cape of Bona speranza, and he shall perceiue the like agreement: But in [Page] sailing from the Cape of Bona speranza, farther Eastward, that sometime they doe finde it otherwise, the cause is the different manner of the scituation of the South, as yet vndiscouered Continent. And wheras in the middest of the Atlanticke Ocean, about 30. leagues Westwards from the Azores, they find no variation at all, no maruell thereof: For it is about the middle distance betweene the two great Continents of America and ours.

Wherefore the round Loadstone is significantly termed by Doct. Gilbert Terrella, that is, a little, or rather a very little Earth: For it representeth in an exceeding small modell (as it were) the admirable properties magneticall of the huge Globe of the earth. Heerein also wee may beholde the reason why, the magneticall needle varieth least in the Aequinoctiall, and most towards the Pole, and in the Poles themselues giueth no direction at all: For proofe heereof, take a needle and place it vpon the Aequinoctial of the stone, there you shal see him stand equally ballanced and very strongly, so that if you turne him from his direction, as soon as you let him goe, hee will presently turne vnto it againe. The reason is, because each Pole doth equally strengthen his correspondent end of the needle. Mooue this needle toward either of the Poles, then doth the neerer Pole strengthen his end of the needle; but the farther (because of the distance) cannot doe the like vnto his, but very weakly, and this needle will not stand any more equally ballanced (as it did in the Aequinoctiall) but that end next the Pole will couch downe, and the other will rise vp. For on the North [Page] side of the Aequator, the true South end is predominant, and on the other the North end hath the mastery. And that this is also in the earth it selfe, all our late Trauellers confirme vnto vs by their daily experience, and all the very Artizans and needlediall-makers in the world must needes be daily witnesses of it. As for example: Let any workman in our Climate make a needle for a diall, when he hath fitted it and placed it on the pinne, that it may stand thereon equally ballanced and paralell to the Horizon touch it with the Magnet, then presently that which pointeth towards the North will hang downe (yea, although you touch onely with the South end) and will not stand, as before the touch equally ballanced and paralell to the Horizon: except you cut or file somewhat from that end, that hangeth downe; or else adde a peece of waxe or some other thing vnto the other end of the needle to counterpoise it, and make it stand equidistant as it did at the first setting on: and this is a thing very certaine, that this Northerly descent of the needle, will be more or lesse in all places of Northerly Latitude: In the greater Latitude the more, and in the lesser Latitude the lesse. But if any traueller carry this needle beyond the Aequator in the like Latitude Southerly, that end which tendeth downewards in the Northerly, will rise vp in the Southerly, and the other sincke downe, euen as much: and the neerer you trauaile towards either Pole, the more, that end which pointeth towards the Pole, will tend downewards: This is most certaine in euery Diall-needle: but a great deale more apparant it is in a long one, [Page] then it is in a short one. Wee cannot find that the property of direction by the Magnetical needle hath beene vulgarly practized (for sailing) much aboue 200. yeeres. And as for the property of declination vnder the Horizon, thereby to shew the Latitude by the Instrument thereunto belonging, it is as yet a very new-come guest into the world, borne and bred with vs in England, and (except it bee in exceeding few mens hands) not yet in vse, much lesse come vnto his perfection. But this it not to be maruelled at: because it is scantly sixteene yeeres olde; neither is it to bee wondred if any Criticall fellowes doe contemne and deride it. Forasmuch as either their want of knowledge, or of patience, will not giue them leaue truely to consider of it. But what Nauigator, or rather Nugator soeuer contemneth it, shall bee sure to repent it if euer hee come to his right wits to consider what it is that he hath contemned. And although the needles for direction and declination doe differ much in their shapes, each from other; yet the properties are both one and the selfe same. For the needles for direction doe decline (as aforesayd) as farre as the vnfitnesse of their forme and placing will permit them: and the declining needle will not worke, but onely in his Magneticall Meridian, which himselfe will finde out, if you turne the Instrument about, vntill the needle shew his least declination vnder the Horizon, and there doe play vp and downe & stop in the end in the same place again. But if you would haue a needle fitted to shew both properties, doe thus, cause a needle to bee made a bout sixe inches long, euen and smooth, sauing that [Page] he must be a little bigger in the middle, then insteed of an Axis (which declinatory needles haue) let him haue a small hole drilled precisely in the middest, and this hole being very small, let it bee somewhat wider outwards on each side then in the middest, (which our workmen call sinckboared) where it must bee left very sharpe, euen almost as the edge of a knife: put through this hole a small verginall lattine wiar, and fit the needle so that it hang precisely euen vpon this wiar, insteed of an Axletree: then touch him with the Loadstone, and you shall presently see the end that should point towards the North, decline or bend downe to his due place of declination, if he be placed in the Magneticall Meridian; set a little peece of waxe or any other thing vpon the contrary part for a counterpoyse that the needle may stand paralell with the Horizon, then if it stand at right angles with that verginall wiar, it is certainly in the Magneticall Meridian: otherwise it will neuer stand at right angles, but will make his sharper angle alwayes towards the Magneticall Meridian. So that hanging in this counterpoise if you turne about the wiar vntill the needle doe make right Angles with it, then doth the needle by his directiue vertue poynt vnto the Magneticall Meridian line. Take off the counterpoise, then it sheweth the declination for that place, and by consequent the Latitude, if you in that manner place him in the Instrument of declination; so that one and the selfe same needle in the same place onely, by taking off, and putting on a little peece of wax, sheweth plainely both those properties of directions and declinations, as in like manner [Page] euery inclinatory needle will doe, if the poynts of his Axis be sharpe, and held in his boxe paralell vnto the Horizon, he will shew both those properties of direction and declination: A fine peece of corcke or leather, or any tough snbstance may serue this needle for a counterpoyse in all Latitudes by thrusting it towards the center in lesse Latitudes, and towards the end in the greater, and I thinke it not impossible, but that a skilfull Geometrician may so graduate the one halfe of such a needle, that it alone with his counterpoyse, may bee a meanes to giue a probable coniecture for the Latitude of any place whatsoeuer.

CHAP. VIII. A discouery of errours committed in making and touching Magneticall Needles and Wyars of sayling Compasses, with an aduise for the true and right making and touching of them.

FIrst the wyars that are commonly made both with vs, and in forraine countries, are of so base and drossie iron, not apt nor sufficient to receiue the tenth part of the vertue that fine steele wyar could doe.

Secondly, the ends of the wiars bee for the most part not filed smooth nor fitted euen together vpon the Axis of the flie; By meanes whereof the touch of the stone is more dully receiued, and the standing [Page] of the flie, the more vncertain, the magneticall force not being in the true axis thereof.

Thirdly, their manner of touching the wiars is altogether pittifull and ridiculous. For with a Magnet hauing a point (for seldome times they haue a stone so well fashioned, that both poynts are eminent) that toucheth to the North (And such an one, though hee bee but weake is preferred among them before another, thogh much stronger that toucheth to the South) they rub to and fro those ends of the wiars, which they would haue stand Northerly. Wherein what doe they else, but play (as it were) fast and loose, not considering (as the truth is indeed) that euery touch from the ends of the wairs towards the Center of the flie with-draweth backeagain that force, which the contrary touch did giue them, and therefore seldome giue they aboue one quarter of that strength, and somtimes not so much, which otherwise with the very same stone they might doe, if they ordered all things as they should: yea, I am infallibly assured (for I haue had certaine experience of it) that with the selfe same stone, you may giue fully as much, and rather more force, touching in such sort, as immediately shall bee declared on the vpper face of the flie: ouer against the wiars (the card being betweene) then they doe by touching the very end of the wiars themselues after their wonted fashion: whensoeuer therefore a needle is to be touched, besides the goodnesse and quantity, you must haue a regard to the forme of your stone, namely, whether it hath both the North and South points eminent and forcible, or onely the one. For if it hath [Page] both, beginne your touching neere vnto the middle pressing the true North point, before specified of the stone all along from thence, vnto the North pointing end of the needle; iterating those touches foure or fiue times, alwayes making some stay with the stone at the end of the needle. The like also must you doe from the middle with the other end of the stone vnto the other end of the needle. But if the stone haue but one forcible point, then if it bee the true North, begin your touching at the South pointing end of the needle, pressing it all along to the North, end, itterating this foure or fiue trmes, and then once or twise onely from the middle vnto that end, If the stone hath but the South point, touch the needle accordingly from the other end; For euen as the vertue of the stone it selfe is a Semidiameter (hauing his beginnning (as before is mentioned) in the center of the stone, euen so the force which he imparteth vnto the needle, is in the nature of a Semidiameter from the middle of the needle. Insomuch that a needle being touched from the middle, but to one end with the North of a stone, it doth not onely cause that end to turne North, but it transmitteth also a contrary force from the middle into the other end of the needle, so that the stone be good, and the needle but of a reasonable conuenient size, as you may euidently trie in euery knife of ordinary goodnesse and length. But a plate of steele made at both ends alike, according vnto the forme heere aboue described, is much better to shew this effect. For when the blade of a knife is of fine mettall, the haft being of course iron, and also of a diuers forme and temper, it is not any [Page]

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way capable of the like force as the blade is, which is the reason that if you touch the blade of an iron-hafted knife from the haft vnto the poynt with a Magnet, it will at the poynt take vp his competent waight, touch it backe againe vnto the vttermost end of the haft it wil take vp little or nothing: Try the like with such a plate or steele, and you shall finde it take vp fully as much at the one end as it did at the other: but if you will bring his touch vnto the middle, it will take vp little or nothing at any end, and nothing at all in the middle it selfe:

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The reason heere of is this, the Magnet giueth his force (Secundum mensuram recipientis) according to the capacity of that which receiueth it, and that euer more after his owne nature, which is to haue his force strong in his ends, and none at all in the middle, if you touch the blade from the middle, with either end of the stone, the other end of the haft will immediate receiue and shew the contrary quality: euen so also will it come to passe, if you make proofe with any Magneticall needle, although that his force will bee faint and weake in comparison of the other. And in your touching you must obserue, that in pressing with the stone from the middle of the needle vnto the end, as you bring your hand backward to iterate the touch, you must lift your hand somewhat high, and not bring it backeward, close to the needle. For that would diminish the strength of the touch. But if that end of the needle be also touched with the other end of the stone, in manner as aboue I haue rehearsed, then shall hee at each end be a great deale the more strong, and the contrary fainter forces shall recoile and settle in the middle of the needle, where they can nothing at all disturbe the motion thereof.

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CHAP. IX. Of the touching with a Laadstone capped and without the cappe.

BY capping, is meant the placing of two peeces of iron handsomely fitted and fastened vpon the two points of the stone, for iron for this purpose is better then steele. And likewise concerning the the waight that is to bee lifted vp, it is better to bee made of soft iron then of steele, and the stone will lift more therof, as long as there is contiguity: but if if the iron and steele be separated from the contiguity of the stone, the steele will alwayes carry at the least tenne times more vertue then the iron, as is before mentioned. Now whether it were best to touch the wiers with a Magnet being thus capped, or with the bare stone it selfe, some there be that make a question. I haue beene tolde by one of great skill and practise, that he found by experience, the Compasse touched with a capped stone, not to receiue his force so well, as the other, and the party comming vnto me, when he was to vndertake a long voyage, to haue his compasse touched, requested mee in any wise to doe it with the bare stone: But yet I thinke it were good, that this bee confirmed by more then one mans experience, before it be beleeued, because by some error he might possibly mistake the matter. Sure I am that the capped stone giueth somewhat more vertue in his touch, and by all experience that I haue made, I finde it to continue as firmely and as [Page] long. Howbeit I referre mee heerein to the ttiall of others also. A man may therefore touch the wiars first with the bare stone, & then with the same being capped, or contrariwise to bee surer of the greater force, and yet if any shall imagine the difference of the strength of the touch, to be according to the taking vp of iron with the cap or without it, he is very greatly deceiued. For I haue osten tried them both, but neuer could see the touching strength in the needle to be increased halfe a quarter more with the cap then without it; whereas I haue alwayes (especially if the stone were very good) found that the stone wil lift at the least ten times as much iron: yea, a great deale more, (and sometimes twenty times) with the cap (if it be artificially fitted) then he is able to doe without it.

Some, who would seeme to be of great skill, haue imagined, that the best way to adde strength to a needle, is with a hammer to giue some forcible strokes to one point of the stone, thereby causing litragges (as it were) or beard, to hang downe from it, & that the needle in his touching, taking some part of that with him, should haue the stronger touch. But they that so suppose deceiue themselues therin: for that beard is nothing else, but the fine dust of the stone, hanging together by vertue thereof: which being separated from the stone (although it were a right good one) is not able any whit at all to turne a needle of it selfe. The triall is soone made by this meanes, let them take of that beard from the stone with a sticke, and lay it vpon the end of a needle not touched, and they shall finde in it no force at all, nay [Page] it is a hurt vnto the needle. For it giueth a superfluous burthen for a small time, and cannot but incumber his action, by reason that euery one of those little parcels of dust (though beaten out at one end) hath also for his small quantity both a North and South vertue. And therefore marreth as much as it maketh at either end of the needle. The proofe heereof is manifest, if you put off that dust or beard vpon a paper, and hold a Magnet therunder, for as you turne towards the paper the North or South of the stone, so will euery one of those particles in like sort turne it selfe, shewing thereby a double nature.

CHAP. X. Of the fashioning of the compasse needle.

THe Compasse needle, being the most admirable and vsefull instrument of the whole world, is both amongst ours and other nations for the most part, so bungerly and absurdly contriued, as nothing more. And therefore entreating now of the nature and vse of the Magnet. I haue thought good, also, to employ my best endeauour, to aduance this noblle instrument towards his highest perfection, being the principall thing, by which the worthy effect of the Magnet, is made most profitable vnto mankinde. Heerein fiue things are to be considered, the substance that it is made of, the forme, the waight, the capitell, and the pin it standeth vpon: The substance [Page] in any wise ought to bee pure steele, and not iron. For most assuredly steele will take at the least tenne times more vertue then iron can doe, but especially if it hath his right temper. And that is this: Heat it in the fire vntill it be past red hot, that it be whitish hot and qnench it in cold water suddenly: So is it brickle in a manner as glasse it selfe, and is at that time incapable of the vertue of the Loadstone. Then must you, laying it vpon a plaine table, warily rubbe with fine sand all the blacke cullour from it, if before you put it into the fire, you annoynt it with soape, it will scale white of it selfe, then heat a barre of iron well neere red hot, and holding one end of the needle with a small paire of tongs, lay the other end vpon the hot barre, and presently you shall see that end turne from white to a yellowish, and after to a blewish cullour, then take that end with your tongs, and doe thlike vnto the other, thrusting it forward vpon the barre vntill the cullour of the whole needle become blewish: then throw it on a table, and let coole of it selfe: and so is he of the excellentest temper, and most capable to receiue the greatest power from the Magnet. If this seeme too curious especially for some fashions of needles, then vse but the hammer hardening (as workmen call it) which is well neere as good. As concerning the forme, diuers men are of diuers mindes, some vse a kind of square one, others a loop (I meane an extended ouall forme) and this is most common. But now a dayes, a narrow straight place (being somewhat broader in the middle) is in great request: Of these three I holde the loope or ouall forme (if it bee well made) to bee the best, which is, [Page] that if it be of steele, his ends be welded together, hauing a lattin narrow plate, issuing from the capitell vnto the middle of the two sides of the Loope, and there riuetted, and riuetting, if it bee handsomely shouldered in by the workman, is better then soadering: because, hauing fitted the lattin plate bearing the capitell vnto the Loope, you may first put your Loope into his temper, and then riuet this vnto him afterwards, which otherwise would bee marred in the fire, and the wide Loope is better then the narrow or the straight plate, and that for two reasons. The one is, hecause, as in a Magnet it selfe, the force that is in the whole body, sheweth it selfe most strongly in his two poles, euen so this being a Magneticall body, doth the like in his ends which are his poles: and the sides of a wide compassed Loope (being longer, then of a narrower) of the same length, in the Axis, must needes containe so much the more vertue; the other reason is, because it supposeth the flie in his circular motion more equally ballanced then the other: and therefore were it not for some other inconueniences, a true circle were best of all, which is that except you marke the two places, that you would haue for the North and Souch, very curiously, you shall neuer giue him the right touch: yea, very exceeding hardly, although you doe marke them; and also the lattin stay, that holdeth the capitell, would bee exceding long and a superfluous burden: but the very best forme of all (as I take it) in all respects is this, a true circle, hauing his Axis going out beyond the circle, at each end narrow and narrower, vnto a reasonable sharpe point, and being [Page] pure steele as the circle it selfe is, haning in the middest, a conuenient receptacle to place the capitell in.

This circle must haue foure very small holes drilled through it, equally distant each from other, for the foure cardinall points, and in both the two poynts, that issue without the circle, being for North and South of equall distance betweene the circle and the end of the poynt two moe, if it be a large one, otherwise one is enough, according vnto this picture following. And this needle is most fit to be vsed for the obseruation of the variation alone without any flie, as I will shew at the latter end of this Treatise.

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[Page]Whensoeuer you wil set this needle vnto the fly, you must put the capitell through the center of the flie very precisely, and placing the points of the Diameter where you will haue them, thrust little small pins through the vpper face of the flie, and those small holes in the needle, the heads of the pinnes will shew you (if the flie bee larger then your needle) at what poynt your needle standeth, and bowing the body of your pinnes (being thrust through those little holes) close to the card below, will keep it steddy at that place, and from warping also. And so foure pins at the foure cardinall points will serue the turne.

Againe, if you please for to place this needle vpon the vpper face of the Card according vnto Steuinius. it is no more but to haue the capitell loose, thrust thorough the center in the bottome of the flie, and the needle placed and fastened on the top, or vpper face of the carde.

But if you will haue a Magneticall needle to serue onely for one size of a flie, the best way is, insteed of the two pinnes in the ends of the Axis, to haue a couple of little halfe staples and a Flower de luce on one of them, as you see in the Loope, riuetted there. That in turning about the needle, they may still keep the flie close vnto it, and so fasten it with a skrew vpon the capitell wheresoeuer you please.

As for his waight it must bee according vnto his largenesse, and the waight is one principall cause, that very large compasses are vnprofitable. For the waight of the large carde, and heauy needle, pressing vpon the pinne, will cause the motion of the flie to be dull and vncertaine, and therefore let the pastboard [Page] be no heauier then you must needes; and for the size of sixe inches Diameter of your past-board, and a needle of that length. I know that a needle of halfe an ounce waight, and halfe a quarterne at the vttermost (if a good workman haue it in hand) will be very fully sufficient, of what forme soeuer.

The capitell ought to be lattin, and hammer hardned, well and truely boared, not too shallow, but of a good conuenient depth and widenesse at the bottome, fitting the pinne it standeth vpon at the top. The pinne ought to be either of lattin, or copper, and not of iron or steele, as some vse; for they are very subiect to rust: and the steele, especially by long vse, will weare a little hole in the top of the capitell, and by that meanes the Compasse becommeth dull, and they hardly (if euer) will find the reason of it; for the hole will bee passing small, and entring an exceeding little way in, and yet disturbeth all. Moreouer, in any wise there must bee alway an especiall diligent care had of fitnesse betweene the capitell and the pinne. Oteerwise, all things else appertaining vnto the compasse are nothing worth. This pinne must bee very firmely fixed in the iust center of the boxe, and the bottome marked, that whensoeuer you take it off to sharpen the pin (which vse will make blunt) you may set him in the same place againe.

As I haue sayd that in a Magnet it selfe, the vertue is in the whole body, and sheweth it selfe most forcible in his poles; euen so likewise our Compasseneedle, being a Magneticall body, sheweth his force in his ends, which are his poles, although that force doth proceede out of the whole body of the Needle. [Page] Which now I thought good to make apparant by an euident demonstration: I caused my workeman to make a needle of a Loop fashion, 8. inches long, or ouall forme in all respects fitted to be set vnto a flie, sauing that there was but one inch or a little more at each end of steele, all the intermediate part between the two ends, being of brasse: These two ends I did touch with the North and South ends of a very good Magnet: And whereas in a true Magneticall Needle, I should haue had but two points, the one North and the other South, this Mongrell yeelded me six, the two ends adioyning vnto the brasse of contrary natures vnto the sharpe points, & would no more doe the office of a Magneticall needle then a woodden sticke, because the vertue was not in the whole, and so communicated vnto the two ends, but each end was a totall of himselfe, being separated, and (as it were) diuorced, the one from all community with the other by that intermediate brasse: the which being taken away, and the two forkes ioyned together for that length, presently they became one perfect true Magneticall Needle, and the vertue of those foure confused points, which ere while was was lost in the forkes, will presently bee found in the two sharpe ends, and now his naturall seats: [Page] Both these ends of steele were fastened vnto the brasse, and then that needle had no Magneticall motion; but being taken off, and ioyned together, they presently (without any further touching of them) became a true Magneticall Needle.

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To conclude this chapter of the Compasse-needle, The needle that is still working vpon his pinne continually will keepe his force better, then that which is otherwise layd vp, although there bee no doubt of the other, for a mans whole age, or longer, if it be of good mettall, and kept from open aire and rust, and from too neere vicinity of iron, but especially of any [Page] Loadstone. No better keeping from rust, then by varnishing him, although it be but with a drop or two of Linseed oyle alone; the needle that is continually vpon his pinne, is still strengthened by the Magneticall power of the earth, setting himselfe alwayes towards the Poles thereof (which the other cannot doe) and needeth onely to haue his pinne sharpned now and then: The which of all the faults incident vnto the Compasse, is most easily and safely amended. And yet, if it bee not very well looked vnto, it disturbeth all the operation of the Compasse more then any other. And diuers wrong themselues in being too busie in often touching of their Compasses, the fault being in this which no touching can amend.

CHAP. XI. A Sayling Compasse fitted for obseruing at Sea the variation, amplitude of either sunne or starres, capes or trendings, &c.

I Haue thought good to conclude this short Treatise of Magneticall aduertisements, with a little additament vnto the ordinary sayling Compasse, fitting him thereby to bee answerable vnto the title heere prefixed, as also with a comparison of the seuerall vses, of the Horizontall and inclinatory needles: Let the glasse of the inner boxe of the Compasse bee of good thicknesse and strength (but yet [Page] cleere) and euen, those that come from Venice for looking glasses before the foile be set on are the best, if a man may haue them large enough. Let this glasse be very well fitted vnto the boxe, and simmond vnderneath vpon the shouldring that beareth vp the glasse, with a mixture of waxe, turpentine, sallet oile and rosin mingled together: or with any other simmon as you shall thinke good, aboue vpon the glasse let there be a ring of thin pastboard, of the bredth of the shouldring vnderneath, in like manner simmoned on: then must you haue a circle of lattin about the bredth of the pastboard ring, of conuenient thick nesse for strength: which must bee diuided into degrees: This circle must haue a plate of latten, of halfe an inch broad or broader, according vnto the largenesse of the circle for strength, that must crosse ouer the middest of the circle, cut out of the same place with the circle, or else so adered with siluer so ader: this must haue a line all along the middest of it, and a little loope at each end cut through the two ends of the loopes being precisely in that line. Last of all, you must haue a moueable ruler with two long folding sights, of about the length of the Semidiameter of the circle in bredth about halfe an inch: the one of them must haue a slit through the length thereof, of about a quarter of an inch broad, as you shall thinke conuenient, and two little holes, the one in the top, and the orher in the bottome, iust in the middle of it, to fasten a string, hauing a very little bead to slide vp and downe vpon it. And this sight must be of the thicker stuffe then the other. For otherwise, because of that which is cut out, it would [Page] be ouerpaised by the other, and so the boxe would swarue towards the other; and the sights must each of them haue a little notch in the middest of the top of them: this ruler must be fastened (but yet so that he may turne about) in the middle of the crosse plate most precisely in the center of the circle, his ends cut, that he may shew the Fiduciall line in the diuisions of the circle, the other sight needeth to bee but a a plaine plate, hauing a line in the middle, from the top to the bottome. The description followeth, being the very same in substance with that, which in the Nauigators Supply, I call the Compasse of variation; although all things easier performed with this, then with that,

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The Picture.

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The Vses.

The Compasse being thus fitted, place the circular needle described in the sixth chapter, vpon his pin alone without any flie. For being disburdened of the card, he will shew his vertue the more strongly, and being of that for me he will ballance himselfe sufficiently.

Place the circle vpon the glasse and pastboard, in such sort that you may turne the circle round about, very close and euen, within the brim of the boxe.

When you will set the same vnto the Compasse, turne the circle about, vntill thorough the Loopes of the middle stay or plate, you see the Axis of the needle right vnder the Fiduciall line of the middle stay, then holding the circle so, turne the mooueable ruler with the stringed sight towards the sunne, vntill the shadow of the string fall vpon the fiduciall line of the moueable ruler, for then doth the end of the ruler, among the degrees, shew the true place or Azimuth of the sunne from the Magneticall Meridian, so that two obseruations, the one in the forenoone, the other in the afternoone, thus made, with the seuerall heights of the Sunne, being one and the very same, halle the differences of those places of the sun, from the Magneticall needle is the variation.

As for example, if the ends of the ruler did cut forty in the forenoone, and fifty in the afternoone, the difference is then, the halfe therof fiue: so much must the variation be Westward.

If a man haue no exact instrument to take the [Page] height of the sunne, hee may make some reasonable shift, by setting the little bead towards the top of the string, that it may in the forenoone cast a shadow vpon the Fiduciall line of the ruler; and marking that place with any thing (as inke or blacke lead) in the afternoone attend, vntill the shadow of the bead (the bead remaining still where it was) fall vpon that place. For then shall you haue that same height, if you will take the amplitude of the suns rising or setting, set the circle, and turne the ruler, as before, vntill the shadow of the string do fall vpon the middle line of the other sight. Then doth the end of the ruler shew, how farre the sunne riseth or setteth from the magneticall Meridian.

When you will take the amplitude of the rising or setting of any starre, you must vse the helpe of another, to holde the circle ouer the needle (as before) and so you turning the ruler, vntill you see the starre in his rising or setting, through the two Notches on the tops of the sights, then doth the end of the ruler shew your desire, The like is to be done in obseruing any cape, or the trendings of any land for the dedescription of any Coast.

CHAP. XII. A comparison of the seuerall vses of the Horizontall and inclinatory Magneticall Needles.

THe Horizontall and inclinatory motions of Magneticall needles are both of them but one [Page] and the selfe same effect of the Magnet or Loadstone, the making of the Horizontall or Diall-needle, is among our artificers very well known and triuiall, only they are to be put in minde that they doe alwaies make them of pure steele and not of iron. But as for the making of the inclinatory needles, it is a very curious peece of worke: It must be of pure steele, and in his right temper, the needle and his axis must bee at right angles the one with the other, and must bee so hanged on the two ends of his axis that hee bee very pliant for his motion, and that (before he haue his touch) he bee so equally ballanced, that the one end be not one iot heauier then the other, for if it be, all the rest is in vaine.

When you will vse the inclinatory instrument, thus you must doe, hanging him by his little ring, turne him about vntill hee make his least declination (or inclination) vnder the Horizon of the instrument: for then is hee iust in his Magneticall Meridian, and there sheweth his due poynt, the which otherwise he can neuer do. But here I must admonish you of two very great errors published in the contriuing of this noble instrument. The one is, that he would haue a little box with an Horizontall Needle fastened vnto the bottome of the inclinatory instrument: for to direct the instrument vnto the Magneticall Meridian: and by his picture of the Instrument, the distance should be but a little more then an inch, where it is impossible but that the one needle must needes disturbe the other, so that neither of them can shew aright, yea, although they were six inches asunder, and more, where the little box will giue little [Page] direction for that purpose? and besides that, it is altogether vnnecessary, because the instrument will finde the Magneticall Meridian, by the least declination of the needle (as is shewed before) vnder the Horizon, without the helpe of any other. The other error is this, that he would haue that end of the needle prepared to hang towards the North, to bee framed somewhat higher then the other, as is vsuall in Horizontall needles: what workman soeuer obserueth this direction, I will assure him, that hee shall lose his labour, and assoone hee may wash a Blackemoore white, as to make such a needle serue that turne. The reason is, because it is onely the magneticall vertue that worketh this effect, the which ouerwaight, in either end of the needle (in this motion) doth vtterly ouerthrow.

For Horizontall needles in our Northerne Climates, it is necessary: but for inclinatory needles, it is vtterly vntrue in all Climates of the whole world wheresoeuer. The motion of the Horizontall needle, is naturally stronger then the inclinatory for two causes, The one is because his motion is onely sidewaies, the which is easier for the Magneticall motion to worke in, then that which is vp and downe, and that there is no difference which way you place the boxe wherein he standeth, so that it bee paralell vnto the Horizon; whereas the inclinatory motion is in a verticall circle vp and downe, and must stand onely in his Magneticall Meridian to performe his office. The other cause is because of the diuersity of their placing in their boxes: for the Horizontal needle standeth more fitter for his motion, being placed [Page] with his capitell vpon the poynt of his sharpe pinne, than the inclinatory can doe, being placed vpon the two ends of his axis, although neuer so neere the poynts: But yet he will doe very well, if he be rightly fitted: And for Nauigation vnder either Pole (if there be any passage that way) it is the onely Instrument of the world. For where the Horizontall needle (or compasse) faileth, he is strongest, for the neerer the Pole, the stronger he is in his Motion, contrariwise, it is with the Horizontall needle or compasse, for he is strongest at the Aequinoctial, and of no force vnder the Pole.

The reason whereof is this, vnder the Aequinoctiall the Horizontall needle standeth paralell vnto the Axis of the earth, and is equally strengthened for his motion with the two poles of the earth: but vnder the poles, hee standeth crosse-wise, at right angles with the Axis, his center representing the very pole of the earth it selfe; so that the Aequinoctiall, and the Horizon being there all one, if the needle should haue any Horizontall motion there, it must needes be an East or West motion paralell vnto the Aequinoctiall, directly contrary vnto nature, and to all Magneticall doctrine.

Yet at the pole, the inclinatory needle is in his cheefest strength, framing himselfe to bee in the same direct line with the Axis of the earth it selfe: so that the vicinity of the neerest pole of the earth, holdeth his conuenient end of the needle most strongly, being nothing at all hindered by the aduerse pole, to affect the vpper (or other) end of the needle. The which in all other scituations either more or lesse it [Page] doth, and especially vnder the Aequinoctiall, where each pole affecting his conuenient end of the inclinatory needle, it must stand very goglingly and vnsteddily for that motion: although most strongly for the Horizontall, if you place him accordingly.

Where hence it followeth, that neere the Aequinoctiall large compasses, and small inclinatories are fittest; and neere the poles large inclinatories, and small compasses are best, for looke vnto what motion the Magneticall force is weakest, the smaller instruments ought for to be applied.

And moreouer, for as much as the Magneticall reuolution of the inclinatory needle, about the globe of the earth maketh his motion for the difference of euery alteration of Latitude neere vnto the Aequinoctiall, farre more large & easier to be discerned, then it can be neere the poles, therefore a lesse Instrument will serue the turne there: And because that neere the pole, his motion for differences of Latitudes are exceeding small, and hard to be discerned. Therefore very large instruments inclinatory are there to bee vsed, especially because the Magneticall strength of the needle for that motion, is there so strong and steddy, that it maketh som recompence for the slowuesse of his moouing. And therefore I suppose that three in Diameter, will serue neere the Aequinoctiall, and fifteene neere the Pole.

And because this great one may be the lesse cumbersome, you may cut off the circle at forty and fiue degrees of each side of the Zenith and Nadir of the Instruments, and yet leaue the needle scope enough, for all Latitudes between sixty Degrees and the Pole: [Page] and for the the steddy standing of the inclinatory instrument at the sea, you may doe thus: about the middle of the instrument (or rather somwhat aboue the middle) let there be two round pins of brasse, about three quarters of an inch long, issue out; and in a box of a sayling Compasse, the inner circle being taken away, make of each side two halfe round notches in the outer circle, there place the Instrument vpon those two pins, the which must haue towards their ends, littles circles cut in, that they slip not out of their rings that they are placed in: then will this Instrument stand as steddy, euen at sea, as the sayling compasse will doe: for the motion of the inner circle is performed by the turning of those two pins in their notches, and the outer circle is common vnto them both, alwaies remembring that you hang some pretty waight in the bottome of the instrument, to make his motion more certaine: If the shaddowing of the box hinder your sight from discerning the point, that the needle standeth at, it is soon holpen with the light of a little waxe candle put downe vnto it: and yet this you ought to vnderstand as aforesayd, that the Horizontal and inclinatory motions are but one and the selfe same effect of the touch of the Loadstone, and one and the selfe same needle will very well performe both motions, namely, the inclinatory needle, not the Horizontall, because his placing vpon the pinne maketh him very vnfit for the inclining motion. But the inclinatory needle resting with one poynt of his Axis (the poynts of his Axis being very sharpe) in his little hole, his boxe being placed paralell vnto the Horizon, will performe the Horizontall motion very well. For being placed with the sharp [Page] point of his axis in that hole, it is all one in effect, as the Horizontal is with his capitel on the sharp point of his pin, but that the one is vpward and the other downward, & yet either of them being as fit for that motion, as the other. Vpon the consideration hereof, my workman of Winchester minding to present Prince Henry with a rare Instrument, contriued an Aequinoctiall Diall & an Inclinatory Instrument both in one, and one needle to serue very well both those turnes. Heerein now appeareth the wonderfull wisdome of our God, in limitting his times and seasons for the reuealing of these wonderfull properties for the vse of men, in this poore stone; namely that aboue 2000. yeeres after that it was knowen and wondred at in the world, for lifting vp of iron (for it was an antiquity in Platoes time) the vse of the Horizontall needle was known, in common vse, scant 200. yeeres agone; and very few yeeres since (yea scant as yet) the inclinatory is in any common vse: and who is there that can behold and consider both these vses, viz. both to shew the quarters of the world (as East, West, North and South, &c.) and also the Latitude of the place: to know both these in any place of the world, bee the heauens neuer so much ouercast with clowds, who is he, I say, that can beholde these two admirable and precious vses performed, euen with the turning of an hand, the which neither the Grecian Philosophers, nor the fine-witted Romans, nor the Persian Magi, nor the Indian Gymnosophists could finde out with all their skill and cunning, but he must needs say with that Kingly Prophet, O Lord, our Lord, how great is thy name through all the Earth, who hast set thy glory aboue the Heauens?

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To the Worshipfull my good friend, Mr. William Barlow at Easton by Winchester.

REcommendations with many thanks for all your paines and courtesies, for your diligence and enquiring, and finding diuers good secrets, I pray proceede with double capping your Loadstone you speake of, I shall bee glad to see you, as you write, as any man. I will haue any leisure, if it were a moneth, to conferre with you, you haue shewed mee more, and brought more light than any man hath done. Sir, I will commend you to my L. of Effingham, there is heere a wise learned man, a Secretary of Venice, he came sent by that State, and was honourably receiued by her Maiesty, he brought me a lattin letter from a Gentle-man of Venice that is very well learned, whose name is Iohannes Franciscus Sagredus, he is a great Magneticall man, and writeth that hee hath conserred with diuers learned men of Venice, and with the Readers of Padua, and reporteth wonderfull [Page] liking of my booke, you shall haue a coppy of he letter: Sir, I purpose to adioyne an appeudix of tx or eight sheets of paper tu my booke, after a while I am in hand with it of some new inuentions, and I would haue some of your experiments, in your name and inuention put into it, if you please, that you may be knowen for an augmenter of that act. So for this time in haste I take my leaue the xiiijth of February,

Your very louing friend, W. Cilbert.

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Faults escaped.

IN the Preface speaking of Claudianus: serediticall for sideriticall. fol. 12. lin. 22. reciprocated for riciprocally. fol. 50. lin. 21. hangings for hugenes. fol. 53. lin. 16. as may be, for as many be. fol. 57. lin. 10. but this is not: for this is not. fol. 68. lin. 19. supposeth the fly, for supporteth the fly. fol: 79. lin. 11. set the same: for set the Sunne. item lin. 27. the difference is then: for, the difference is ten. fol. 82. lin. 8. higher: for, heuier. fol. 84. lin. 26. three in Diameter: for, three inches in Diameter. fol. 85. lin. 10. littles circles: for, little circles. The last line saue one of D. Gilberts letter, act: for, arte.

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A BREIFE DISCOVERY OF THE IDLE ANIMADVERSIONS OF MARKE RIDLEY Doctor in PHISICKE vpon a Treatise entituled, Magneticall Aduertisements.

—moueat Cornicula risum

Furtiuis nudata coloribus—

LONDON, Printed by Edward Griffin for Timothy Barlow, at the signe of Time in Paules Churchyard. 1618.

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TO THE RIGHT NOBLE AND WORthy minded industrious Gentlemen, and others who are any way addicted vnto MAGNETICALL Knowledge.

SO it is that for a long time I haue bin greatly delighted in the contemplation of the properties and vertues of this admirable creature of God which we call the Magnet, or Loadstone. And as my leisure and occasions haue serued by conference from time to time, with the skilfullest Nauigators of our age, by reading all the Treatises (as came vnto my knowledge) of such as had written thereof, and therewithall trying by practise the truth of those things which I doubted of, and lastly finding some things by my owne experience of good importance by others not at all [Page] mentioned. The chiefe of these which I iudged profitable for common vse I did set forth in a small Treatise intituled Magneticall Aduertisements. And although of mine owne louing affection towards such (as yee are) I haue bin alwaies ready to further you in these knowledges the best I could, yet I doe assure you faithfully, that diuers of good iudgment, learning, and eminent place, (vnto whom I communicated my experiments) very vehemently vrged my publishing of them.

A copie of this Treatise being by stealth written out of my Manuscript, by one that vnderstood it not, and by that meanes committed diuers errors, this Doctor Ridley deuoured some of them, and by his endeuouring to square my propositions according to his owne conceipts, and so superciliously to controll (and censure the things which he vnderstood not) he hath missed of the truth very farre and wide, and hath herein wronged both himselfe, and mee, and his readers, but most of all his beleeuers; and yet such is his kinde disposition, that he hath purloyned out of the scambled copie of my Treatise, for to adorne his owne Treatise of Magneticall bodies and Motions all these that follow; as in his Treatise,

Fol. 7. The hilly knobbes, and angulous parts &c. for 17 lines.

Fol. 8. The greater stones &c. 5 lines.

Fol. 9. Steele and yron &c. 4 lines.

Fol. 10. The 14. 17. 18. 19. figures are mine.

[Page] Fol. 18. 19. The 1. 2. 3. 7. waies are mine, the 4. Doctor Gilberts.

Fol. 22. Euery part and peece of a Loadstone, &c. 7 lines.

Fol. 27. If a wyer be touched &c. 5 lines.

Fol. 30. & 31. It is to be obserued in the fashion of a Magnet &c. 16 lines.

Fol. 36. For although that naturally &c. 9 lines.

Fol. 51. & 52. Also if a Magnet be fastened &c. 4 lines.

This practise is profitable for Trauellers &c. 14 lines moe.

Fol. 63. 64. The best way to touch &c. 11 lines.

And some haue thought it better &c. 14 lines.

Fol. 66. Set two Loadstones &c. 3 lines.

Fol. 71. An Adamant doth loose much of his vertue &c. 3 lines.

Fol. 72. That 20. Chapter (onely a few words chopped and changed) is whole mine.

Fol. 83. And for this cause the Adamant &c. 3 lines.

Fol. 89. A peece of Steele well tempered &c. 2 lines.

The two next are his owne, and very absurd.

Fol. 90. Now it is to be obserued &c. 10 lines.

Fol. 95. The needles and compasses &c. 14. lines.

So that it cannot but seeme to any indifferent person very strange, that Doctor Ridley would publikely so traduce mee, and that by name, and so contemptuously [Page] in his friuolous Animaduersions, and could neuer hit vpon my name, no not so much as once to acknowledge it in all these things which he hath by stealth learned of mee, and inserted into his Magneticall Motions for his owne, the which with their consequents if you withdraw from his Treatise, you will leaue his motions very dull. For except this Ridley, had ploughed with my Heifor, hee had not knowne my Riddle. Sic vos non vobis.

In my aduertisements indeed, I made mention that some body had in this manner dealt euilly with mee, and I reproued certaine faults that some body had committed, especially in the fundamentall Magneticall heare-sayes of misnaming of the true North and South, in Magnets and Magneticall bodies, and in making the Inclinatory needle with the one end heauier than the other, and some others: But these two especially, for because they doe draw on many others, as they doe both in his Booke, and wheresoeuer they shall be admitted, they will increase like a snow-ball, waxing still greater as they goe, and all his dawbing of them with his vntempered morter in his silly Animaduersions do amend the matter nothing at all, but make it farre worse than before. For the common good, I might not let them passe vnreproued, and yet I would not publikely name him, but vsed this word somebody. The like himselfe hath, viz. Some say, some labour to cleare, some thinke &c. in his booke meaning mee, being not contented onely to vsurpe [Page] that which was properly mine for his owne (as aforesaid) but also hee tooke vpon him (although very ignorantly) to confute some of mine vnder these termes, and this onely out of a stolne Manuscript. Whereas all men know that Manu-scripts ought to be vncontrould vntill the Author hath published them, who may alter and change things in the meane space as he thinketh good.

He stileth himselfe principall Phisition vnto the Emperor of Russia, the which many men wonder at, being so yong as he than was, and supposed that he went ouer only as Phisition vnto our Merchants there, that he should in so short a time become that Emperors principall Phisition. If he were, he sped better then Bomelius did, who is said to haue died there in that cold climat of the extreamest hot kinde of Calenture.

Out of all question, somewhat it is more then ordinarie, that maketh him of so hauty a spirit, so to braue the world with such prodigious assertions of his Magneticals, in, and aboue the Moone; the earths Magneticall circular Motions, and his paltry abusing of the holy scriptures to support his lunaticke fictions vnder the name of Magneticall Philosophie.

There are yet two texts of Scripture, which it is a wonder how they escaped him; the one is in Iosuah 10. ver. 12. and the other is in Esay 38. ver. 8. In the one: That the Sunne and the Moone stood still the space of a whole day: The other, that the shadow in Achas diall went backe 10 degrees, [Page] and the Sunne in the skie returned 10 degrees by the which he was descended.

For it is his guise to make contrary conclusions vnto that which the Scriptures affirme, and therefore blame him not, if he doe so despise Aristotle, who neuer taught any such Logicke.

Now therefore that yee may in few words vnderstand the vntruth of the earths Magneticall Motion, that is so mainely emblazoned by him, and the weaknes of my Animaduersors Magneticall skill, you must know, that the Magneticall Motion is a naturall inclination of two Magnets or Magneticall bodies, that may freely moue, respecting the one the other within the Orbe of their forces with their convenient ends, that is to say, the North end of the one alwaies respecting the South of the other.

If the two Magnets or Magneticall bodies be of like quantitie, forme, and goodnes, their Motions will be of like quicknes of the one towards the other; but if they differ in any of these, their Motions will be so much the slower.

Now forasmuch as all Magneticall motions are alwaies respectiue of the one Magnet or Magneticall bodie towards another, it followeth by necessarie consequent, that no Magnet or Magneticall body, can either moue, or be moued of it selfe, but is vtterly voide of all intrinsecall or selfe-Motion, the true and onely cause of his Motion being euermore without it selfe.

And therfore mine Animaduersors selfe-motion [Page] of the Globe of the earth circularly, by Magneticall vigour, in the which hee doth so gallantly triumph; is but an idle figment, and a meere Chimaera: but his definition of Magneticall bodies is very sutable vnto it; viz. very monstrous; namely, That wee define to be a Magneticall body, which doth remaine and place it selfe in one place, or kinde of situation naturall, not alterable, as all starres doe, and the great Regent globes of Saturne, Mars, Iupiter, the Sunne and the Earth doe: or such, as with respect and attendance follow other globes, as the two starres which support Saturne; the foure attendants vpon Iupiter, lately discouered by the truncke-spectacle; the two trauersers about the Sunne, called Venus and Mercury; and the Moone, which doth follow or goe about the earth, and respecteth the same alwayes with one Pole, and therefore hath a peculiar Magneticall vertue, that guideth her in this kinde of situation.

Auditum admissi, risum teneatis amici,

Any man that considereth this goodly definition, being the foundation and ground of his Magneticall discourse, and the very first sentence of his booke, and many the like fancies in his Motions and and Animaduesions will easily discerne what his Magneticall skill is, and what a vanity it were for me, to spend any precious time to confute in particular such vnreasonable and senselesse opinions, which haue more neede of Helleborus to purge them out of his head, then Arguments to confute them in his booke. And in his friuolous animaduersions [Page] seeking to maintaine his former errours, and he being so snappish to haue them amended, hee maketh them ten times worse then they were before, and far more palpable: But my tetricall Animaduersor must be ruled by reason, and affoord all those his patience that do beleeue the holy Scriptures, which flatly doe denie the Earths motion, and affirme the motion of the Sunne, Moone & Stars, in the whole current thereof, as Psal. 19. 6. 104. 5. Iosua 10. 12. 13. 14. Esay 38. 8. &c.

Also that hee will giue men leaue to credit their senses, in matters subiect vnto sense, and not repugnant vnto reason; and that he will not be offended with those who do pitifully laugh at his Magneticall Astronomy, with those topsituruy motions, like

Voluitur lxion, & se sequiturque fugitque.

For although some great learned men in those Sciences, haue vsed the supposed motion of the earth, for an Hypothesis, seruing their ready calculations; as they haue done also their supposed Epicycles, for the motions of the Planets and their courses: yet that is no reason for to auouch them for to be in themselues true and reall things, according vnto some mens vaine fancies, who doe argue after this sort.

It is an easier matter, and more (as they say) agreeable vnto nature, for so small a body as the globe of the Earth is in comparison of the heauens, to mooue circularly in the space of foure and twenty houres, then it is for the huge Vniuerse so to doe; and that which is done with lesse hazard, is to bee preferred [Page] before the like, which may not bee performed without feare of a greater danger, with diuers other reasons like vnto these.

But although such as these are, may goe current in a mechanicall Trades-man shop, yet they are very insufficient to bee allowed for good, by men of learning, and Christians by profession, who know right well, that it is great folly for to oppose that which we call difficult, vnto an omnipotent power, Who stretcheth out the heauens like a curtaine, and spreadeth them out as a tent to dwell in, Esay 40. ve. 22. He stretcheth out the North ouer the empty, and hangeth the earth vpon nothing, &c. Iob 26. ver. 7.

And that which we call Nature, it being nothing else but Gods ordinance; there can bee nothing contrary, but all things agreeable vnto nature, which God hath ordained. But God hath ordained the motion of the Sunne, Moone, and Stars (as aforesayd) and the vnmooueablenesse of the earth; therfore this is more easie, and more agreeable vnto nature; which is preserued onely by obeying Gods ordinance, and heerein onely that consisteth, and hath her being. And that the earths magneticall vertue hath no power at all to performe or help any such motion, as is also before made manifest.

But that mine Animaduersors magneticall skill is ascended vp into our Moone it selfe; yea, and yet higher, farre beyond the Moone, vnto the other Planets and Starres, and into euery one of them, this is such a point of his Magneticall Philosophie, that would make Stupidity it selfe astonished to heare of it.

[Page]There was (as the Poets faine) a certaine King of Phrygia, that had a gift giuen him of the Gods, at his owne request, that whatsoeuer he touched with his body should be gold, but by that meanes being ready to starue, because his victuals were also turned to gold, he entreated earnestly that he might surrender his gift.

It seemeth that mine Animaduersor endeauoureth for to make shew, that he hath a stranger gift; namely, that by his very lookes (for his lookes, with his Truncke-spectacle, are his meanes) he can turne all things to be Magneticall, that hee doth earnestly behold; He hath scowred the Heauens already, euen from the one end vnto the other, that both Planets and Stars are become magneticall in his head; what tumultuous stirre may they breed there, no man can tell, it is his safest way to confine his Magnetismes vnto the earth, as their naturall seat, and not suffer them to clamber vp into the skies, where they haue nothing to doe, lest that infinite dispersion of his magneticall knowledge, doe in the end ouercharge his braine, and make him magnetically mad, or at the least to incur the censure of him that said,

Delphinum siluis appingit, fluctibus aprum.

As therefore whilst his wits are yet his owne, it is his surest way (like the King of Phrygia) to surrender that gift againe, to leaue his trifling with the holy Scriptures, and to bee no more a censuring Animaduersor in matters that he hath but small skill in: and that he will heereafter learne to be wise vnto sobriety, Metirise quemque suo modulo ac pede verum [Page] est. And forasmuch as his animaduersions containe nothing at all, of any truth and importance against mine Aduertisements, but onely many ignorant, many wilful mistakings, contradictions & cauillings, and maintainings of his former absurdities, the which the more they are stirred by him, the more they stinke. I will content my selfe with this breefe discouery of this Animaduersor, and his animaduersions, and so to leaue him for this time peeping in his truncke-spectacle at his celestiall magneticall regent globes, with his proud motto:‘Non sufficit orbis.’ To try whether he can yet finde vs heere hence any more new glorious dreames, wherby he may either encrease the number of the hundred of merry tales, or els augment the noble history of Huyn of Burgis.

And whereas he chargeth me opprobriously for to haue in my Treatise nothing of mine own, but all of other mens, and some of his: mine answer is, that he knoweth in his owne conscience (if he haue any) that hee speaketh a manifest vntruth, contrary vnto his owne knowledge in both. Yea, I am verily perswaded, that if he would but giue his owne conscience, leaue to speake out, it would ring him a tale in his eare vnto this effect: That he himselfe knoweth right well, that where my knowledge (euen such as it is) in these matters faileth: all the store of skill that he hath, cannot aduance it, no not so much as one strawes bredth, notwithstanding all the great countenance hee setteth on it, with his swelling titles of his Magneticall bodies and motions, and his [Page] Aristarchicall censuring of my Aduertisements.‘Nil dignum tanto feret hic promissor hiatu.’ And for my iust defence, I will rehearse but these few things (yet such as are of principall importance in this Art) whereas I could name diuers other.

I was the first that made the inclinatory instrument transparant, and to bee vsed pendant, with a glasse on both sides, and a ring on the top, whereas Doctor Gilberts hath but of one side, and to bee set on a foot. And moreouer, I hanged him in a compasse box, where with two ounces waight he will be fit for vse at sea.

Another is, that I was the first that found out and shewed the difference betweene iron and steele, and their tempers for magneticall vses, which hath giuen life and quickning, vniuersally to all magneticall instruments whatsoeuer.

I was also the first that shewed the right way of touching magneticall needles.

I was the first that found out and shewed the peecing and cementing of Loadstones.

I was the first that found out and shewed the reasons why a Loadstone being double capped, must take vp so great waight.

These things (yee worthy Gentle-men) haue I mentioned onely to giue you content and satisfaction: For although my magneticall knowledge be no manner of way gainefull vnto me, as all that are acquainted with me, know how little I doe esteeme of it in any such respect, yet forasmuch as I haue published my Magneticall Aduertisements of my [Page] very earnest affection towards such as yee are, and dedicated them vnto one right worthy Gentle-man of your Society in steed of all, euen for your sakes I could not suffer my paines and good will towards you, to be so scornfully trampled vnder foot (without some gaine-saying) and pratled out of conceit with cauilling only, and multiplicity of vaine words and peeuish brauadoes, The Lord prosper you in all laudable knowledge and vetuous practise.

Yours in all hearty affection▪ W. BARLOW.

Information about this book

Title statement

Magneticall aduertisements: or Diuers pertinent obseruations, and approued experiments, concerning the natures and properties of the load-stone Very pleasant for knowledge, and most needfull for practise, of trauelling, or framing of instruments fit for trauellers both by sea and land. Whereunto is anexed a breife discouerie of the idle animaduersions of Mark Ridley Dr. in Physicke, vpon a treatise entituled Magneticall aduertisements.

Barlow, William, d. 1625.

Edition statement

1618

Publication

Publisher

Text Creation Partnership,

Place of publication

Ann Arbor, MI ; Oxford (UK) :

Date

2003-09 (EEBO-TCP Phase 1).

ID [DLPS]

A04327

ID [STC]

STC 1444

ID [STC]

ESTC S100862

ID [EEBO-CITATION]

99836689

ID [PROQUEST]

99836689

ID [VID]

973

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This keyboarded and encoded edition of the work described above is co-owned by the institutions providing financial support to the Early English Books Online Text Creation Partnership. This Phase I text is available for reuse, according to the terms of Creative Commons 0 1.0 Universal. The text can be copied, modified, distributed and performed, even for commercial purposes, all without asking permission.

Series

Early English books online.

Notes

(EEBO-TCP ; phase 1, no. A04327)

Transcribed from: (Early English Books Online ; image set 973)

Images scanned from microfilm: (Early English books, 1475-1640 ; 1265:12)

Source

— Magneticall aduertisements: or Diuers pertinent obseruations, and approued experiments, concerning the natures and properties of the load-stone Very pleasant for knowledge, and most needfull for practise, of trauelling, or framing of instruments fit for trauellers both by sea and land. Whereunto is anexed a breife discouerie of the idle animaduersions of Mark Ridley Dr. in Physicke, vpon a treatise entituled Magneticall aduertisements., Barlow, William, d. 1625., Barlow, William, d. 1625. Breife discovery of the idle animadversions of Marke Ridley. aut, Gilbert, William, 1540-1603. De magnete.. The second edition..

Extent

[16], 86, [4]; [2], 13, [1] p. : ill.

Printed by Edward Griffin for Timothy Barlow, and are to be sold at his shop in Pauls Church-yard, the signe of Time,. London :: 1618.. (Dedication signed: William Barlowe.) (A reissue of "Magneticall advertisements", 1616, and "A breife discovery of the idle animadversions of Marke Ridley", 1618; the title page of the first work is cancelled with the new general title page. The first work is partly compiled from: Gilbert, William. De magnete.) (Identified as STC 1444a on UMI microfilm.) (Reproduction of the original in Cambridge University Library.)

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