thin surfaces of light be in an infinitely small part of time, it may take a hundred or a thousand years to diminish the sun's diameter one inch. You will find something of these abstract speculations in the treatise I mention.

I have much reason to apprehend the errors of the press, when I reflect on the manner in which the Indian History has been printed, with such gross errors in things obvious to the meanest understanding. Mr. Dodsley promised to get some person of learning to correct the press. Perhaps the difficulty he meets with in this is the reason that the impression was not completed in the beginning of March, though begun in December.

I shall be exceedingly disappointed if it do not meet with censure. I have laid my account with it, not only with unjust and injurious censure, but that many errors may truly be discovered, and that it will require much correction. It is impossible to avoid errors in things of this nature, more especially in a path not trod in before, and where I had no one to assist me to review and examine the work, a difficulty an author cannot abor under in England.

I have received a copy of the translation of my first piece into High Dutch, with animadversions on it at the end of it, printed at Hamburg and Leipsic, in 1748; but I do not understand one word of them. I find my name often in company with those of very great men; Newton, Leibnitz, and Wolfius. Leibnitz's Monades offers mankind a new doctrine, which perhaps you may have seen, and is of great repute in Germany. The animadversions end, "Magnis lumen excidet au sis," which, being in Latin, I understood.

The person in the Boston paper, who wants a fuller description of the poke-weed or phytolacca, than that

given in the magazine, must have but little skill in botany; for I am confident the description is sufficient for a botanist to distinguish it from any other plant whatsoever. I know that some people have thought that the poke-weed is mechoachan; but they, who think so, know little of plants.

This comes to you on account of Dr. Douglass. He desired me to write to you for what you know of the number that died of the inoculation in Philadelphia, telling me he designed to write something on the smallpox shortly. We shall both be obliged to you for a word on this affair.

The chief particulars of our visitation, you have in the public prints. But the less degree of mortality than usual in the common way of infection, seems chiefly owing to the purging method designed to prevent the secondary fever; a method first begun and carried on

* In a letter, dated February 17th, 1752, Dr. Perkins had written as follows; "The small-pox threatens spreading here, and some of our people are coming into a course of tar-water as a preparative. If your doctors have found any benefit by any medical management previous to the common way of infection, I should be glad to know it for the sake of such as are not pleased with inoculation, and for the meliorating of this too. I believe something may be done in this matter, and would promise trials of every thing likely to succeed; though I differ from my brethren in the affair of diet."- EDITOR.

in this town, and with success beyond expectation. We lost one in eleven; but, had we been experienced in this way, at the first coming of the distemper, probably the proportion had been but one in thirteen or fourteen. In the year 1730 we lost one in nine, which is more favorable than ever before with us. The distemper pretty much the same then as now, but soine circumstances not so kind this time.

If there be any particulars which you want to know, please to signify what they are, and I shall send them.

The number of our inhabitants decreases. On a strict inquiry, the overseers of the poor find but fourteen thousand one hundred and ninety whites, and one thousand five hundred and forty-four blacks, including those absent, on account of the small-pox, many of whom, it is probable, will never return.

I pass this opportunity without any particulars of my old theme. One thing, however, I must mention, which is, that perhaps my last letters contained something that seemed to militate with your doctrine of the Origin, &c. But my design was only to relate the phenomena as they appeared to me. I have received so much light and pleasure from your writings, as to prejudice me in favor of every thing from your hand, and leave me only liberty to observe, and a power of dissenting, when some great probability, might oblige me; and, if at any time that be the case, you will certainly hear of it.

I am, Sir, &c.

JOHN PERKINS.

TO JOHN PERKINS.

Concerning the Small-pox in Philadelphia.

SIR,

Philadelphia, 13 August, 1752.

I received your favor of the 3d instant. Some time last winter I procured from one of our physicians an account of the number of persons inoculated during the five visitations of the small-pox we have had in twentytwo years; which account I sent to Mr. W. V., of your town, and have no copy. If I remember right, the number exceeded eight hundred, and the deaths were but four. I suppose Mr. V. will show you the account, if he ever received it. Those four were all that our doctors allow to have died of the small-pox by inoculation, though I think there were two more of the inoculated who died of the distemper; but the eruptions appearing soon after the operation, it is supposed they had taken the infection before in the common way.

I shall be glad to see what Dr. Douglass may write on the subject. I have a French piece printed at Paris, 1724, entitled, Observations sur la Saignée du Pied, et · sur la Purgation, au Commencement de la Petite Vérole, et Raisons de doubte contre l'Inoculation. A letter of the Doctor's is mentioned in it. If he or you have it not, and desire to see it, I will send it. Please to favor me with the particulars of your purging method, to prevent the secondary fever.

ments.

I am indebted for your preceding letter, but business sometimes obliges one to postpone philosophical amuseWhatever I have wrote of that kind are really, as they are entitled, but Conjectures and Suppositions ; which ought always to give place, when careful observation militates against them. I own I have too strong

a penchant to the building of hypotheses; they indulge my natural indolence. I wish I had more of your patience and accuracy in making observations, on which alone true philosophy can be founded. And, I assure you, nothing can be more obliging to me, than your kind communication of those you make, however they may disagree with my preconceived notions.

I am sorry to hear, that the number of your inhabitants decreases. I some time since wrote a small paper of Thoughts on the Peopling of Countries,* which, if I can find, I will send you, to obtain your sentiments. The favorable opinion you express of my writings may, you see, occasion you more trouble than you expected from,

Sir, yours, &c.

B. FRANKLIN.

TO CADWALLADER COLDEN.

Remarks on Mr. Colden's Theory of Light. lation of Electrical Papers into French.

Trans

Philadelphia, 14 September, 1752.

DEAR SIR, When I had read your favor of May the 20th, I resolved to read and consider more carefully Sir Isaac Newton's Optics, which I have not looked at these many years. I delayed answering, till I should have an opportunity of doing this, but one thing or other has hitherto hindered. In the winter I may possibly have more leisure.

In the mean time I would just mention, that the interposition of a hill between a bell and the ear does

* See this paper in Vol. II. p. 311.