IT is a satisfaction to me to find, by your paper of the 26th instant, that so reverend and learned a person as Mr. Prince sees no reason to withhold his approbation of the account which I have given, in my printed Lecture, of the natural causes of Earthquakes, he himself being of much the same opinion; as appears by a Sermon of his. And I lay the greater weight on his opinion in this case, because it seems to have been formed upon mature deliberation: At least, he has had no want of time for full consideration, having continued in this opinion above 28 years together. The first paragraph of this paper, which makes a full quarter part of the whole, is almost wholly taken up in giving a very handsome character, and therefore no doubt, a very just one, of this Sermon, as filled with Philosophical and Theological erudition. It lets us know, that the Rev. Author, having given a brief account of all the same things, which I afterwards said somewhat more particularly, with relation to the causes of earthquakes, considered in a Philosophical view; did not stop there, but went on to consider them as a student of Divinity, in a manner which is here displayed at large. Had I known of this learned Sermon is season, I might have adorned my discourse with another illustrious name, besides those of NEWTON, BOYLE, &c. I might at the same time have corroborated that particular in it, which relates to the existence of subterraneous caverns, by the testimony of an unexceptionable witness, See marginal note, p. 10. of the Sermon refer'd to. who▪ "in accounting for these natural causes," as he by a remarkable peculiarity of phrase expresses himself, "goes no further than he has seen with his eyes." In these respects▪ might this learned sermon have added to my discourse, both ornament and strength. But alas! so scanty was my knowledge, that some weeks had passed, after the delivery of my discourse, before I saw, or so much as heard of this Sermon; tho' it was printed above 28 years ago. To prevent the like unhappy accidents for the future, I would humbly propose it to the consideration of this Rev. Author, who, I doubt not, is very willing that posterity, as well as the present age, should enjoy the advantage of his learned labors; whether it may not be advisable for him to deposite a copy of this Sermon in the public library of Harvard-College, for the benefit of my Successors and of that whole Society, in all succeeding generations.

But notwithstanding the approbation so graciously not with-held, and amidst a great deal of unmerited encomium, for which I return this Rev. Divine my most humble thanks, I have the mortification to meet with some grounds for complaint in this paper. I might offer it as a matter of complaint, that this Rev. Gentleman represents me to have considered, agreable to my academical office, natural causes MEERLY or chiefly in a Philosophical view, as the powers and operations of material substances: Whereas agreable to his peculiar office, as a student of Divinity, he went on [in his Sermon aforesaid] to consider those material causes as acted upon—by GOD, &c. The word, MEERLY, here used does not convey a just idea, either of the nature of my academical office, or of my conduct in it. The consideration of a DEITY is not peculiar to Divinity, but belongs also to natural Philosophy. And indeed the main business of natural Philosophy is, to trace the chain of natural causes from one link to another, till we come to the FIRST CAUSE; who, in Philosophy, is considered as presiding over, and continually actuating, this whole chain and every link of it; and accordingly, I have ever been careful to give my discourses this turn. To consider natural causes meerly as the powers and operations of material substances, would be to consider them, not in a Philosophical, but in an atheistical, view. I know it will be said, that the force of the word, MEERLY, is qualified by the other word, chiefly, here joined with it. But these words do not well consist together, the ideas signified by them mutually excluding each other; so that whenever one of them can be used with propriety and truth, the other cannot. I might, I say, have offered this as a matter of complaint. But as I find below, that by several passages in my Lecture, this Rev. Divine doubts not my full concurrence with him in asserting the agency of GOD, in all the operations of nature; I shall only say, that the rest of the sentence without this word, MEERLY, would have given a juster representation of the case; nor would the omission of this word, as I humbly conceive, have at all weakened this Gentleman's paper. But I proceed to other matters.

I soon find myself charged with mistakes;—with having mistaken this Rev. Divine in several places of his late appendix, and in general in the design thereof. And it is repeated a little lower, that I have unhappily mistaken him in several parts of his said Appendix. That mistakes, and unhappy ones too, have been committed in this affair, I make no doubt. Where those mistakes ought, in justice, to be placed; I shall now, with this Rev. Divine's indulgence, and with the liberty of "a free inquirer after truth," proceed to examine.

This charge of mistakes consists of two parts. 1st, That I have mistaken him in several places of his Appendix. And 2dly, That I have mistaken him in general, in the main design thereof. Let me consider each of these charges distinctly.

The first is, That I have mistaken him in several parts of his late Appendix. As this Rev. Divine has not thought proper to point out any of these several mistakes, I am forced to guess at them as well as I can. What number of particulars he usually includes in this indeterminate word several, or what idea he affixes to it, I am not able to say. But in the present case, I am sure that he cannot include more than two; because I am sure that I have quoted and remarked on no more than two passages of that appendix (distinguish'd from the P. S. to it, as he himself distinguishes them in this very paper); and I am sure too, that he will not tax me with having mistaken him in those other parts of his appendix, concerning which I have said nothing. One of these quotations is from the upper part of p. 21 of his appendix, concerning the waving about of the electrical substance in different parties in the earth below, &c. The other is from the lower part of his p. 20. concerning an equal distribution of this substance in the earth, not producing any concussions there. The greatest possible number of mistakes, therefore, that can be supposed, is but two. Now if the Reader will please to observe, that both these quotations relate precisely to one and the same thing, namely, whether there be an equal distribution of this substance in the earth below, or an unequal distribution of it into different parties; he will immediately see, that this reduces the two supposed mistakes to one. And if he will farther consider, that the whole argument of my appendix, except what relates to this Gentleman's Postscript, is levell'd against this single principle, viz. That there is an unequal distribution of this electrical substance in the earth, in the sense there explained; and that this Rev. Divine avows this to have been, and still to be, his principle, by saying in this paper, that he cannot yet see, that I have clearly proved the contrary conclusion: If the Reader considers this, he will clearly see the necessity of making a farther reduction, and of bringing the supposed one mistake, to none. I cannot yet see any way of reconciling this charge with truth, but by supposing that this learned Divine has mistaken the usual acceptation of the word, several; and that he here annexes the same idea to it, as is annexed to the word, none, by other people. I must therefore, till I am better inform'd, take the true meaning of these passages to be, that I have UNHAPPILY not mistaken him at all. So much for the charge of, several mistakes. Proceed we now to

The Second,—the charge of mistaking in general the main design of that appendix. I am in no pain lest this part of the charge should be made out against me; because I have not said one word, from which it is possible, for this Rev. Divine, or any body else, to collect what I thought was the main design of that appendix: And until my opinion in this matter be known, it will be no easy task, I apprehend, to prove that I have been mistaken in it. But though I have no where said what I thought the main design of that appendix was, yet I have said that, from which it may be plainly enough collected what I tho't it was not; namely, that it was not to assert or prove that the electrical substance must be admitted as the cause of earthquakes. This was sufficiently discovered by the beginning of my Appendix, which was, that "A little tract" (meaning Mr. Prince's Appendix and Postscript)—HINTED at a different cause of earthquakes. I used this word, HINT, on purpose to guard against this very mistake of my meaning, into which this Rev. Divine has unhappily fallen. It is a word that I could never have thought of using, had I imagined that the main design of his appendix was, to assert and prove that a different cause of earthquakes must be admitted. To say that the main design of a book is HINTED at in it, would be such a strange abuse of language, as I hope I shall never be guilty of. This word, HINT, plainly shewed, that I took the discoursing of the electrical substance as the cause of earthquakes, not to be the main design of that appendix. My not declaring, what I took it's main design to be, did not proceed from any backwardness to do it, but purely from it's being intirely foreign from the design of my appendix. It was not my main design, nor any part of my design, to write an appendix in opposition to the main design of Mr. Prince's Appendix, as he seems to think, when he calls my Appendix an answer to his; but only to rectify the two particulars, mentioned in the title of my Appendix, in which I apprehended this learned Divine to have been mistaken. And it was with an express intention to give notice to every Reader that the main subject of my appendix was different from his, that I gave my appendix a different title. There could not, therefore, be the least occasion for me to say▪ what I thought the main design of his appendix was. However, since he has drawn this matter into public debate, I will do it now: And I do it in full security, that I cannot even then be convicted of having mistaken it; unless he has mistaken it himself: Because in this last paper he explains it to be the same as I have all along supposed it to be. I did, when I wrote my appendix, and do still suppose, that the main design of his appendix was, by the help of those nine particulars, which two unequal clouds, unequally charged with the electrical substance, and at a proper distance from each other, will act as if they perfectly knew, to introduce a NEW proof of the continued agency of GOD. A design this, truly excellent and noble, and every way worthy of this Gentleman, in his complex character of Philosopher and Divine! This was a design, which tho' I think I should not have prosecuted exactly in the same way as this Rev. Gentleman has thought proper to do, yet I had no inclination to interfere with, at all; and with which, when conducted in a manner that appears to me agreable to truth, I trust I shall never interfere. But to prove the continued agency of God, there was no necessity of making a new supposition concerning the causes of earthquakes; since all the phaenomena of nature afford proofs, and the same kind of proofs too, of that point. For in every case, without the exception of a single one, where bodies are moved to or from each other, according to fixed and determinate laws, it may with the same propriety be said, that the bodies act as if they perfectly know what those laws are. The sulphureous, nitrous and other substances, with which this Rev. Divine was satisfied, in accounting for earthquakes, 28 years ago, would therefore have answered the general design; tho' perhaps it might be somewhat difficult to form so surprizing an argument from them, or to make out the same number of particulars, in which these "act like perfectly knowing and spontaneous agents."

We have at last got thro' the article of mistakes; and the Reader is by this time qualified to judge, to whose account the mistakes, which have arisen in this debate, are to be placed. To his decision, therefore, I chearfully refer it.

In explaining what was the main design of his appendix, this Rev. Divine tells us, that HE only supposed, that from Mr. Franklin's discoveries—It seems very likely, that this electrical substance, with the others mentioned [the sulphureous &c.] "is a principal instrument in producing earthquakes." Between this passage and the appendix there seems to be a variance. That told us, that "Mr. FRANKLIN suggested the likelihood" of this hypothesis. For such is the grammatical connection of the first paragraph of the appendix.—Mr. Franklin—has—surpriz'd—the world with his discoveries of the Electrical Substance:—and with good reason suggests, that—it seems very likely that this Electrical Substance, with the others mentioned, is a principal instrument in producing earthquakes. Indeed, I am not certain that I can clearly prove this conclusion, from grammatical connection; because I find by several instances in this learned Divine's last paper, that he is invested with the prerogative of dispensing sometimes with grammatical niceties; which perhaps may have been done in the present case. However, as I know no better way to come at the meaning, I shall follow this, for the present. Here then I am held in suspence as to the real Author of this suggestion or supposition, not daring to follow either the appendix or the last paper, lest I should be charged with mistaking the other. But I should be very glad to have this matter cleared up; and to be certainly informed whether it were Mr. PRINCE or Mr. FRANKLIN that suggested the great likelihood, that the electrical substance is a principal instrument in producing earthquakes. My reason is, that if it were Mr. FRANKLIN, I would humbly request to be informed, in which of his books he has made this suggestion; being extremely curious to know what is said upon this subject by a Gentleman, not less noted for the solidity of his judgement, than for the acuteness of his penetration.

The next passage that calls for notice, is, that notwithstanding all my granted Premisses about Electrics and Non-electrics; he cannot yet see, that I have clearly proved this conclusion, that there can be no unequal distribution of this electrical substance in the earth or terraqueous globe . What the true reason should be, why this Rev. Philosopher, whose quicksightedness as to some things is not to be questioned, does not see the force of my argument, I will not presume to guess. Upon the most careful review, I can discover no defect in the argument itself. In the course of that argument, I considered two different suppositions, which I thought were the only possible ones that could be made, as to the situation of electrics and non-electrics in the bowels of the earth; which suppositions were, that a non-electric is intirely surrounded with electrics; or, that it is not intirely surrounded with them; and in each of these suppositions shewed, from the laws of electricity, and with some tolerable degree of clearness, as I flattered my self, that there could be no unequal distribution of the electrical substance in the earth. And that this argument was not intirely deficient either in clearness or strength, I have the satisfaction since to find by the effect it has had in convincing some others, who, were I at liberty to name them, would, I dare say, be universally allow'd to be very competent judges of the goodness of an argument. If this Rev. Divine can show any third supposition that can be made, different from these two, viz. that a non-electric is intirely surrounded with electrics, or, not intirely surrounded with them; I shall make no scruple to confess, that my argument is not adapted, in any part of it, to reach this third case. But to attempt to vindicate it, as it relates to the two suppositions on which I founded it, before I am shewed the particular parts in which it is supposed to be defective, would be but a mispence of time. I shall therefore say nothing upon it, till I see those Remarks and Questions, which this Rev. Divine gives me some reason to expect I may be honor'd with hereafter. As to which, I can only say at present, that whenever he shall think it a proper season to communicate them, I shall be ready to attend him; and tho' he may perhaps ask more questions than I can answer, I shall endeavour to give, both him and the public, the best satisfaction I am able. And if it shall then appear, that I have advanced any thing, either in point of fact or argument, which I am not able to defend; I will give it up honestly and frankly, without any evasions, tergiversations, or subterfuges whatsoever.

Though I am very willing to have the present debate brought to a speedy issue, yet to desire this Rev. Gentleman to write again upon this subject before he has "considered" it, might carry the appearance of disrespect;—an imputation, which I would carefully avoid, as inconsistent with the profound veneration I have for the united characters of a Philosopher and a Divine. However, I cannot conceal my astonishment at the reason here given for not persuing these "inquiries into the natural causes of earthquakes at present." It is, for fear of diverting the minds of any, in this extraordinary season, from attending to matters of infinitely greater moment; and from improving their present, awakened apprehensions and impressions &c. Lest, while for the gratification of their curiosity, they are busied in enquiring into those material instruments of earthquakes, their minds should be taken off from their just concern and labour to secure their eternal interest. Upon which I would ask, Is it a more "extraordinary season" now, than it was 28 years ago, when this Philosophical Sermon was printed? or than it was two months ago, when it was reprinted, with the addition of a curious Appendix and Postscript? Were not people, as both those times, under as "awakened apprehensions and impressions" as they are at present? and did not this Rev. Divine know it? If there was no danger then of diverting the minds of any from attending to matters of infinitely greater moment, by Inquiries into the natural causes of earthquakes, whence arises the danger now? Can there be a fitter season for humble inquiry into the works of GOD, than when the minds of people are under "awakened apprehensions and impressions" of His greatness, His majesty, His power, His goodness, as supreme GOVERNOR and continual PRESERVER of universal nature? And have not such inquiries, when properly conducted, a direct tendency to promote, and not to obstruct, Religion?

Is it not evident, that this Rev. Divine has, within the two last months, intirely changed his sentiments with respect to the influence which Philosophical inquiries have upon matters of religion? Had he been of the opinion he has newly embraced, before the publication of his Appendix and Postscript, all this debate had been prevented. Now it is this change that astonishes me; because some other parts of this paper afford strong evidence, that he is a Gentleman not much given to change. If any of our Readers should inquire, whence this sudden change of sentiments can proceed; I am not able to inform them, and so leave it. Far be it from me to insinuate, that it proceeds from the present exigency of his affairs.

The last paragraph of this paper relates to the Postscript about the iron-points; as to which this Rev. Divine is exceeding short. Upon this head, we hear not a word of, unhappy-mistakes of his meaning, either in several particulars, or in the main design; not a word of, conclusions not clearly proved; nor of, remarks and questions, put off for the present, but which may be proposed as some uncertain time hereafter. As to all these things, there is a deep silence. The proper conclusion from which, as this Rev. Divine did not care to speak out plainly, so neither do I. But altho' appearances are in some measure saved by saying, "he is yet uncertain about the influence of points in earthquakes";yet we may be very sure, that he does not retain any real suspicion of danger from them. Let his own words vouch for this. "As I never", says he, "was against erecting them" [the points] with a due submission to the sovereign Will and Power and Government of GOD in nature, in humble Hopes of greater Safety, and with a becoming Trust in HIM, and not in them; I am of the same Mind still. Is it possible for any man, who has a suspicion, that iron-points expose the parts of the earth, where they are erected, to more earthquakes, and more shocking ones—is it possible for such a man to be for erecting these points "in humble hopes of greater safety"? But I forbear to press the argument any farther.

To conclude, I cannot but esteem it an high felicity to have rescued this worthy Divine from the panic which had seized him, when he wrote his Postscript about the iron-points; and by him, consequentially, a great number of others, especially of the more timorous Sex (so extensive is his influence!) who have been thrown into unreasonable terrors, by means of a too slender acquaintance with the laws of electricity. It affords me a singular pleasure, under the groundless charges which have been laid upon me, to reflect, that I have not written altogether in vain.