DESCRIPTION OF THE SALT SPRINGS.

THE Salt Springs, which I propose now to examine, are situated in the north western part of the State of Newyork, in the country of Onondaga, at the head of the Onondaga, [Page 7] or Salt Lake, about 150 miles from the city of Albany, in lat. 43° 4′ 30″ N. long. 1° 5′ W. of Philadelphia.

The Onondaga Lake is about six miles long, and on an average one mile wide. It is supplied with water by a num­ber of rivulets, and empties itself by a short outlet into the Seneca river, sufficiently large to be navigated with bat­teaux. The water is transparent and abounds with fish; its taste is perfectly fresh, notwithstanding the numerous salt springs which continually flow into it. This is the case however only on its surface for I am informed that by sink­ing a corked bottle to the bottom of the lake, and then with­drawing the cork, salt water is brought up. Water impreg­nated with salt being specifically heavier than fresh would naturally move along the bottom and continue there, un­less brought up and mixed by some great commotion of the waters. This can plainly be discerned, where the salt water issues from the springs into the fresh water of the sur­rounding marsh; various light substances may be seen swimming some distance below the surface between the salt and fresh water; these substances being of a specific gravi­ty, lighter than the one and heavier than the other. The bottom of the lake where it can be seen in shallow places, has a white appearance almost peculiar to itself, except the spots which are covered with a singular species of moss, growing there in abundance. This white appearance is [Page 8] most probably produced by the precipitation of a calcareous earth from the water; and this conjecture is confirmed by the circumstance of the salt water holding a larger quantity of lime in solution.

The head of the lake is surrounded for some distance by marshy and swampy ground, interspersed with a few large trees and bushes, but abounds most with flag and wild grass. The Salt Springs issue for the most part from this marsh, near the banks by which it is bounded, at various distances from the waters of the lake. The principal springs, which are most highly impregnated with salt, and which supply the greater number of the manufactories at present established, issue from the marsh in a group at the foot of the declivity formed by the upland on which the village of Salina is situ­ated, commonly called the Salt Point, near the place where the Onondaga Creek empties itself into the lake. There are however numerous other salt springs discovered in dif­ferent parts of the marsh; some along the shores of the lake, several miles down, others a considerable distance up the Onondaga Creek; and what is remarkable, they have been found to rise in shallow places from the bottom of the lake, at some distance from the shores. All these however are not so strongly impregnated with salt as those before mentioned at the Salt Point.

[Page 9] The springs issue from the black mud which composes the marsh, by small orifices, apparently in a perpendicular di­rection. The manufacturers, for the conveniency of pump­ing the water into conductors which lead to the evaporating pots, construct cisterns or reservoirs where the springs appear. The superfluous water from these as well as that from the surrounding marsh, is emptied into a small bay or harbour a few yards from the springs, large enough to contain fifty or sixty boats at once, as if designed by nature for the express conveniency of exporting salt. This bay communicates with the lake by a short outlet, but sufficiently deep to be navi­gated with the flat boats and batteaux which are usually employed.

The marsh surrounding the springs for a few yards, is en­tirely destitute of grass and all other [...], except [...] samphire, (Cr [...]hmum of Linnaeus;) and when the sun shines, the water is evaporated from the surface of the mud, leaving it covered with christalized salt, resembling hoar frost.

It is remarkable that all the dead vegetable substances which happen to be within the reach of the salt waters, assume a reddish brown colour; hence all the brushes, old sticks and various kinds of timber scattered about the springs, and even the troughs (generally made of white cedar) through which the water is conducted to the boilers, in a short time [Page 10] acquire this colour: not only dead vegetable substances, but even growing vegetables and stones are thus changed in ap­pearance. I have observed, however, that this red colour extends no farther than the surface of both vegetables and stones. The internal part of old wood being invariably black, and that of the stones natural. It may therefore be produced merely by the deposition of a red, earthy matter, upon these various substances.

Salt springs are discovered and characterised by those who search for them, by the absence of grass and flags, by the red colour of the mud, and old wood which may happen to be scattered there; if the marsh be covered with water, by its temperature being much colder than the stagnant water; and also by the appearance of a continual bubbling from the bottom, in consequence of the air which is perpetually ex­tricated from them.

Vegetable substances appear to putrefy much sooner in the vicinity of the salt waters than in any other places; hence, even when the weather is but moderately warm, there is al­ways a very disagreeable putrid smell near the springs, and in mid-summer I am informed it becomes almost intolerable. We could very plainly observe this disagreeable odour as soon as we approached near the outlet of the lake, in going up the Seneca river in the month of June. On account of [Page 11] the shallowness of this outlet, it is probable that the salt water which had been gliding along the bottom of the lake, became there mixed with the fresh, and by exposure to air, excited an incipient putrefaction in the various substances capable of undergoing that process. Nothing of the offen­sive smell was perceived while we were crossing the lake, but it recurred again in a much higher degree as soon as we ap­proached the shore near the salt springs. This may perhaps be accounted for by the well known experiments, which prove that a small quantity of salt dissolved in water, accele­rates and promotes putrefaction; whereas a stronger impreg­nation becomes highly antiseptic. This putrefactive process takes place in an extraordinary degree, only in those situa­tions where the salt waters mix with the fresh; for the un­diluted waters of the springs themselves are sufficiently im­pregnated with salt effectually to preserve both vegetable and animal substances; being stronger than the pickle usually made to preserve beef. As a proof of this I need only men­tion, that in almost every spring there are occasionally found several dead frogs, that have accidentally plunged into them instead of fresh water, and instantly died. These frequently remain there for a long time, perfectly preserved, without any putrid smell.

The bottoms of the springs appear to be composed of sol­id rock, for by running down an iron instrument into them, [Page 12] it uniformly proceeds six or seven feet through the mud, and then is obstructed by a solid obstacle, which can plainly be felt to be stone; I am informed by those who have dug into the springs, that the streams of salt water appeared to rise perpendicularly from the bottom, whereas those of fresh water where they happen to occur in these places have a horizontal direction, and are more superficial. This obser­vation confirms the supposition that the salt water is forced directly upwards, through the interstices of the calcareous rock, which probably covers a large body of salt; and that the veins of fresh water, being entirely separate, make their way in a horizontal direction from the springy ridge at a small distance; this too will explain how it happens that several good fresh springs without a particle of salt are found at the foot of this ridge, not ten yards from some of the salt springs. Sticks of wood have been dug up from the bottom of some of the salt springs, which have been found incrusted with a substance of a metallic appearance; I could not pro­cure any of these for examination.

The reservoirs and springs of salt water are usually cover­ed with a pellicle of extreme tenuity, reflecting the rays of light in variegated colours, similar to that which occurs up­on the surface of the water in [...]ar vats: this is probably a bituminous oil which rises with the water from the bowels of the earth.

[Page 13] There is continually emitted from the bottom of the springs a large quantity of an aerial fluid which bubbles from the surface of the water. By inverting a bell glass in the springs, I collected in a very short time a considerable quantity. As it rises from the bottom it appears to be en­tangled by the mud, for by running down a stick repeatedly it is disengaged, so fast, as to cover the water with bubbles, resembling a boiling pot. A burning candle being put into this air, thus procured, was extinguished in an instant of time, and that after the vessel had stood open for a little while. From this experiment I conclude it to be fixed air,^* (carbonic acid gas;) characterised, by its being total­ly incapable of supporting combustion, and by its greater specific gravity than atmospheric air, in remaining for some time at the bottom of the vessel although it was open. It is no uncommon thing to find this air generated in the bowels of the earth in great abundance. It frequently manifests itself in deep mines, and sometimes proves fatal to the min­ers: hence they call it choak damp, to distinguish it from the inflammable air which also sometimes occurs, this is called fire damp; it is supposed also that it is this same air [Page 14] which issues from the famous Grotto del Cani in Italy, and is so noxious to animal life.

This air as it rises through the water does not however appear to incorporate with it, at least not in any perceptible degree; for the water has none of that sparkling brightness, nor the pungent odour, which is characteristic of this gas when uni­ted with common water; on the contrary it appears flat and heavy. The air in this instance is probably produced by the decomposition of lime-stone, which we know contains it in abundance, and the salt water holds a considerable por­tion of lime in solution. It is probably partly dissolved by means of the muriatic acid, (spirit of sea salt,) this having a stronger attraction for lime than the aerial acid, would dis­place it, and set it at liberty to be dissipated in the form of air.

Of the Nature of the WATER.

THE appearance of the salt water when viewed in a glass, is nearly transparent and colourless, though not perfectly so; for when compared with common pure water, it appears to have a perceptible bluish tinge, probably owing to its greater density. When poured from one glass into another, it has somewhat of an oily aspect, being similar to the vitriolic (sulphuric) acid, which latter from this peculiarity has been improperly denominated an oil. The water taken pure from [Page 15] the springs, is destitute of any odour. Its taste is extremely salt, and leaves a very slight bitter impression upon the tongue; but it is much less nauseous than sea-water. If it be true, as Professor Berghman supposes, that the peculiar nauseous taste of sea-water, which is often attended with vomiting, and which is not found at all, or but very little in water taken up at the depth of sixty fathoms, is produced by the putrefaction of the immense number of fish, worms, insects and vegetables that grow, live and perish in the sea, and quickly putrefy on the surface, by exposition to the air, assisted by the saltness of the water; then it is evident that the water of these springs must be entirely destitute of it; for it issues clear and pure immediately from the earth, and is of itself sufficiently strong to prevent putrefaction.

The temperature of the different springs, which I exam­ined by an accurate thermometer of Farenheit's scale, was from 50 to 53 degrees, as will appear more particularly from the subsequent table of specific gravities of the different springs to which their temperatures are severally annexed. This is the usual heat of most springs of every kind, and hence has been deduced the interior temperature of our earth, which is supposed to be uniformly and invariably the same, except where it may be altered by local causes. But it ought to be remembered that the temperature of the waters issuing from the bowels of the earth, may be considerably [Page 16] influenced by the superficial acquired heat of its surface as they approach towards it, particularly in the summer season; and hence the true internal temperature is probably some degrees colder.^*

[Page 17] The specific gravity of the water of a number of distinct springs was ascertained by a hydrostatic balance constructed with mathematical accuracy and sensible to the least varia­tion in the weight of the water, as exhibited in the following table.

The gravity of the water of Mr. Geddis's spring was as­certained after a shower of rain, which perhaps, diluted it a little. Mr. O. Blennis's and Danforth's being on the verge of the waters of the lake, appeared to be mixed with a por­tion of fresh water.^*

[Page 18] It will be unnecessary from the design of this essay to give a minute analysis of the waters of these springs, and equally so to recount the experiments or describe the processes which were used to ascertain their contents. It will be sufficient barely to mention that I obtained from half a pint of this water 551 grs. or about 1¼ oz. avoirdupoise, of salt, and 26 grs. of calcareous earth (line;) equal to 8816 grs. or 30 oz, and 76 grs. of salt to the gallon, and 416 grs. or nearly 1 oz. [Page 19] of calcareous earth. It contains also a very minute portion of vitriolic (sulphuric) acid, probably united with the fossil alkali in the form of Glauber's salt (sulphat of soda;) but it is not impregnated with any iron as might be supposed from the colour which it imparts to substances with which it comes in contact; for neither the Prussian alkali nor the tincture of galls produce any change when mixed with the water, both being accurate tests to discover the smallest quantity of this metal. From the foregoing analysis it appears that the pro­portion of salt held in solution by the water of these springs amounts to more than 1-6 of its own weight: this far exceeds every salt spring that we have ever heard of, and sea water I believe, usually contains no more than about 1-30.

With respect to the origin of the salt water we have noth­ing but conjecture. It is very probable, however, that it proceeds from a solid body of salt, at no great distance from the place where it issues from the earth; or else it would be difficult to conceive how it becomes so strongly impregnated, almost to saturation. The rocky bottom of the springs and the apparent gushing of the water through its apertures, af­fords a presumption that the body of salt may be immedi­ately below, covered only by a stratum of calcareous rock; for salt mines are most frequently found covered and inter­spersed with [...] of lime-stone. At the distance of about half a mile from the salt point, there is a [...] lately sunk [...] [Page 20] the earth; it is four or five feet wide, descends twenty feet perpendicularly, and then appears to take an oblique direc­tion downwards. This is supposed by some to have been caused by a vacuity underneath, produced by the dissolution of a body of salt in the waters which lead to the springs. If it had any communication with them, I supposed there would issue from it an air of the same nature. To ascertain this I let down a burning candle into the pit, but it continued to burn without any diminution of its lustre; a sufficient proof that it contained none of the fixed air which the springs emit in such abundance.

Of the SALT MANUFACTORIES.

THE marsh from which the principal springs proceed, is bounded, as I have before observed, by a steep bank of clayey ground, about thirty or forty feet above the level of the lake, forming the up-land on which the village of Salina stands. From this there is a gradual ascent for a consider­able distance back, commanding a beautiful prospect of nearly the whole lake. The soil is clay, destitute of stones, and for the most part, oak timbered. Immediately below the declivity, on the borders of the marsh, and as near the springs as the ground will admit, are situated the buildings which are destined for the manufacturing of salt. They are constructed of wood, generally about twenty feet wide, and [Page 21] of various lengths, according to the number of furnaces they are intended to contain; in one of them there are forty evaporating pots: The furnaces are placed along one side of the building, with their mouths opening into it. The other side is generally made use of to deposit the salt for the purpose of draining off the brine, and allowing it to dry, immediately after it is emptied out of the evaporating vessels. The furnaces are built of stone, and two or three pots or kettles (such as are used to boil pot-ash) containing each about eighty gallons, are usually placed over each of them. Between each two furnaces a large trough is placed, from which the water is drawn into the boilers as often as it is required. These troughs are kept continually filled with water by means of gutters, into which it is pumped out of the springs. The furnaces being supplied with fuel, and the pots filled with water, they are allowed to boil briskly, and after a little while the powder scratch (as it is called) consist­ing of calcareous earth, begins to precipitate to the bottom; this is taken out as fast as it is formed, by means of large iron ladles. By the time this has all fallen down, the salt begins to chrystalize; the pots are then suffered to boil gently, till nearly all the water is dissipated. The salt is afterwards taken out and deposited in proper places to drain off the brine and suffer it to dry. Nothing now remains in the pot but a small quantity of bittem, which is thrown away, and [Page 22] the same process is repeated. Part of the calcareous matter which is precipitated in the operation of boiling, adheres firmly to the bottom of the kettles, and becomes nearly as hard as stone, hence it is called stone scratch. It is necessary to separate this every few days, by means of a sharp iron pick; for if suffered to remain too long, it becomes so thick as to retard the boiling. Thus simple is the whole process which is used in manufacturing a beautiful white granulated salt from the water of these valuable springs. Each boiling of a ninety gallon pot, yields about a bushel and a peck of salt; but there are many in use of a much smaller size; they may therefore be allowed on an average to make one bushed each by every boiling; they may be boiled down two or three times in twenty-four hours. The whole number which have lately been employed in the different manufactories, is one hundred and fifty-seven; with these of course about 70,000 bushels of salt may be manufactured yearly. From the report of the Superintendant to the Legislature, it ap­pears that ‘the quantity of salt made, fold and delivered from the 20th day of June, 1797, to the 3d day of Febru­ary, 1798, being six months and fourteen days, (in which period of time is included the sickly season of said place) being manufactured in 157 kettles of different sizes, is 25,474 bushels.’ From the above statement he calculates that ‘the probable proceeds of all the kettles now occupied [Page 23] at the different salt-works, may be estimated at about 60,000 bushels of salt per year.’ ^*

By reason of the immediate mixing of the waters of the salt springs with the waters of the marsh, it was impossible to make any computation of the quantity which they yield, or the amount of salt that may be made from them; but it must be very great; for one of the springs alone, judging from the stream which it emits, it is supposed could scarcely be lowered by the operation of an ordinary pump. Of many of the springs now used by the manufacturers, but a small part of the water is consumed; besides a great many others that remain unoccupied: and it may be presumed that many more will be discovered from time to time. This abundant quantity of the water will permit a very great in­crease of the manufactories; and a production of salt to an immense amount.

We come now to examine whether the present method of manufacturing salt admits of IMPROVEMENT, and whether other means might not be devised, that would be attended with superior advantage. But this important branch of the [Page 24] subject cannot be fully discussed within the limits of this memoir: I have perhaps already trespassed upon the time of the Society; it must therefore be left at present in a great measure to the ingenious manufacturers, who are more im­mediately interested. To them it is recommended as a sub­ject well worth their greatest attention. They will doubt­less strive to obtain every information respecting the various methods and different instruments that have been used from time to time in foreign countries, where this article has been manufactured. They will likewise enjoy all the advantage to be derived from their own experience; and it is especially by information and experience that manufactures and arts of every kind can be brought to the greatest perfection. I shall take the liberty, however, to suggest only one or two improvements, which now occur to me as of primary im­portance. The first is, to substitute large flat pans, in the place of the pots which are now altogether used. The most approved pans of this kind employed in foreign manufacto­ries, a model of which I have now before me, are made of an oblong form, flat at the bottom, with the sides erected at right angles; the length of some of them are 15 feet, the breadth 12, and the depth 16 inches. They are commonly made of plates of sheet-iron about one-third of an inch thick, joined together with nails, and the joints are filled with a strong cement. A pan of these dimensions will contain [Page 25] more than 1,400 gallons, and 4,200 gallons of water may be evaporated in 24 hours, which would produce at least 60 bushels of salt. It is probable that it would require no more fuel for this purpose than is required to boil down six of the pots now used, which yield only about 12 bushels.

Another improvement which would probably be attended with great advantage, is the erecting partition walls between the openings of the furnaces and the boilers, by these means the dust and ashes which is continually dispersed through the air from the flues of the furnaces, would be prevented from falling into the water, and impairing the beauty and quality of the salt. Very little attention is given to this circumstance, as the works are conducted at present: not only the boilers are continually exposed to impurities, but the salt also after it is manufactured is frequently left in the same rooms with the furnaces, and by these means becomes almost covered with ashes before it is taken away.

I might mention several other things tending to facilitate and improve the operation of extracting salt from the water of these springs; but they will readily occur upon a little reflection, to those who are engaged in the works.

Notwithstanding however all the improvements which can be suggested and the inventions that can be had recourse to, these manufactories will still be attended with considerable la­bor [Page 26] and expence, and probably will become more so in course of time with the scarcity of wood for fuel. At present the salt is afforded for sixty cents per bushel with ample profit; but it is not to be expected that this will be of long dura­tion, for the increasing distance of carrying the wood to supply the furnaces will proportionally increase the ex­pence of manufacturing, and of course the price of the salt. At some future time necessity will perhaps compel us to resort to some other means of evaporating the water, without the aid of fire. But before this period arrives, the hardy sons of industry may possibly penetrate into the bowels of the earth, and possess themselves of that solid body of salt which is buried beneath: and who knows but there may be concealed such an immense mine of this valuable article, that in process of time, when a large portion of it shall have been consumed, there may be sufficient room (like in the salt mines of Cracow in Poland) for a subterranean ‘town, with a market place, a church, a river and a famous statue,’ so beautifully described by the poetic Darwin.

[Page 27] Dr. Hutson in his theory of the earth, supposes that these immense masses of rock salt may have been produced by the evaporation of sea water, in the early ages of the world, by means of subterranean fires. Dr. Darwin seems to be of the same opinion, and observes that this idea is confirmed by a fact mentioned in M. Macquarts Essais sur Mineralo­gie, who found a great quantity of fossil shells principally bi-valves and madre-pores in the salt mines of Wialiczka, near Cracow. If we apply this theory to the objects under consideration, we may naturally suppose that the large cav­ity in the earth now occupied by the waters of the Ononda­ga Lake, on the borders of which the salt springs appear, has at some early period been the mouth of a tremendous volcanic eruption, producing by its intense heat a sudden evaporation of a large quantity of sea water, which it hap­pened to meet in the interior parts of the earth. This idea, if admitted, will at once account for the formation of a lake, and the production of a salt mine; at the same time that it leads the mind with more facility to conceive of the proba­ble magnitude of the latter. Great indeed must be that body of salt, which we may suppose to be produced by a torrent of heat near six miles in diameter, volatilizing and dissipating the waters, and leaving the fixed and solid materi­als in accumulated heaps. Or is there some still undis­covered chemistry of nature, that elaborates salt from the [Page 28] materials of this earth, and collects it in such huge masses as to be proof against the wastes and depredation of time. For in whatever way it may be produced, our idea of the quantity remains undiminished, when we consider that it has probably for ages since, impregnated the copious streams that flow from these springs, almost to complete saturation.