abroad without them. I am in such haste, as we have already begun to print, and have done five sheets.* The whole work will make betwixt four hundred and five hundred pages quarto, and we shall not have done quite so soon as Christmas. For the same reason, I must beg you would also send me, as soon as you conveniently can, the two last numbers of the work which I left in the hands of Dr. Watson to be transmitted to you. I am now wholly employed in revising and correcting. I defer drawing up the account of my own experiments, till I have some more in pursuance of them and several others. In about a week I shall betake myself to experiments in good earnest; but I have no expectation of doing much more than I have done. Upon Mr. Price's letter I sent the mark that was actually made by a chain, when a discharge was sent through it. I have several times since I came home got three and almost always two concentric circles, upon the metal knobs with which I make discharges. If I verify your experiments on the electrified cup and animal fluids, may I publish them as yours in some proper place in my work? I shall soon go about them. Have you procured the list of books written on the subject of electricity, or the remainder of Wilkes's Treatise? Dr. Watson has sent me a curious tract of Johannes Franciscus Agua, which I am now digesting. In your note on one of my numbers you say, you question whether an æolipile will turn the same way, whether it draw in or throw out the water. I had tried it before I wrote the paragraph; you may depend upon the fact. I hope to find more of your excellent remarks upon the two numbers in your hands. I am, dear Sir, &c.

JOSEPH PRIESTLEY.

* Priestley was now engaged in writing his History of Electricity, which was the work here alluded to. - EDITOR.

P. S. Since I wrote the letter, I made a discharge through a chain, that lay on this side of it. At the moment of the discharge, the whole appeared like a bright flame. From a, where the chain was returned, it was thrown back as far as b. I have tried the same several times since, laying one half of a chain parallel to the other, and marking exactly how far it reached upon the table; and always found the middle part pulled back about one inch and a half, as if a sudden jerk had been given to it. Indeed it was manifest, by comparing the link with the mark, that every link had moved a little. Must not that have been effected by the links repelling one another while the stroke was passing? Is not the paper really burnt? Was not the chain made superficially hot? And does not the electric shock pass chiefly over the surfaces of bodies? so that small bodies will be melted, because they have most surface in proportion to their bulk. The faint marks at a distance from the rest are not made by handling. They are just as the discharge left them. Indeed you will find they are not easily effaced. The wire of the chain is not so thick as the marks.*

TO GEORGE CROGHAN.

Conjecture as to Elephants being Natives of America.

SIR,

London, 5 August, 1767.

I return you many thanks for the box of elephants' tusks and grinders. They are extremely curious on

* On the face of the original letter, from which the above has been copied, the marks of the chain are still distinctly visible as here described, it being seventy-one years since the experiment was performed. The marks are of a yellowish green color. — EDITOR.

.

many accounts; no living elephants having been seen in any part of America by any of the Europeans settled there, or remembered in any tradition of the Indians. It is also puzzling to conceive what should have brought so many of them to die on the same spot; and that no such remains should be found in any other part of the continent, except in that very distant country, Peru, from whence some grinders of the same kind formerly brought, are now in the museum of the Royal Society. The tusks agree with those of the African and Asiatic elephant in being nearly of the same form and texture, and some of them, notwithstanding the length of time they must have lain, being still good ivory. But the grinders differ, being full of knobs, like the grinders of a carnivorous animal; when those of the elephant, who eats only vegetables, are almost smooth. But then we know of no other animal with tusks like an elephant, to whom such grinders might belong.

It is remarkable, that elephants now inhabit naturally only hot countries where there is no winter, and yet these remains are found in a winter country; and it is no uncommon thing to find elephants' tusks in Siberia, in great quantities, when their rivers overflow, and wash away the earth, though Siberia is still more a wintry country than that on the Ohio; which looks as if the earth had anciently been in another position, and the climates differently placed from what they are at present.

With great regard, I am, Sir,

Your most obedient humble servant,
B. FRANKLIN.*

* The bones referred to in this letter were presented by Dr. Franklin to the Royal Society. In the Philosophical Transactions, (Vol. LVII, p. 464,) they are described in a paper communicated by Mr. Peter Collin

DEAR SIR,

TO M. DALIBARD.

London, 31 January, 1768.

I sent you some time since Priestley's History of Electricity, under the care of Mr. Molini, bookseller on the Quay des Augustins. I hope it got safe to Paris, and that you have reviewed it. I wish the reading of it may renew your taste for that branch of philosophy, which is already indebted to you as being the first of mankind, that had the courage to attempt drawing lightning from the clouds to be subjected to your experiments.*

In our return home, † we were detained a week at Calais by contrary winds and stormy weather, which was the more mortifying to me, when I reflected that I might have enjoyed Paris and my friends there all this time, and yet have been as soon at London. As I became in arrear with my business by so long

son.

At the beginning of that paper, Mr. Collinson says; "George Croghan, who is a deputy of Sir William Johnson, the King's superintendent of Indian affairs in America, in the course of his navigation down the great river Ohio, after passing the Miami river, in the evening came near the place where the elephants' bones are found, about four miles southeast of the Ohio, and about six hundred miles distant from and below Pittsburg; from the nearest sea-coast at least seven hundred miles. Next morning he met with a large road, which the buffaloes had beaten, wide enough for two wagons to go abreast, leading straight into the great licking-place, to which the buffaloes and all the species of deer resort, at a certain season of the year, to lick the earth and water from salt springs, that are impregnated with nitrous particles." Mr. Collinson's account is accompanied with drawings of some of the bones. They were at first supposed to be the bones of elephants, but it was afterwards ascertained that they belonged to an extinct race of animals called by naturalists the Great Mastodon: EDITOR.

* See, in Vol. V. p. 288, an account of M. Dalibard's experiments at Marly.-EDITor.

† Dr. Franklin had recently returned to England from a tour in France.

- EDITOR.

VOL. VI.

X

an absence, I have been necessarily much occupied since my return, and have therefore postponed from time to time (and so long that I am now ashamed of it) the purpose I had of writing soon to you, to express the sense I have of your kindness to me when a stranger at Paris, and of the many civilities I received from you there and from Mrs. Dalibard, which I assure you have made a lasting impression on my memory. I beg you will both of you accept my sincerest thanks and acknowledgments. The time I spent in Paris, and in the improving conversation and agreeable society of so many ingenious and learned men, seems now to me like a pleasing dream, from which I was only to be awakened by finding myself at London.

With the greatest esteem and best wishes for your health and happiness, I have the honor to be,

Dear Sir, &c.

B. FRANKLIN.

TO CADWALLADER EVANS.*

On the Colica Pictonum, and Pernicious Use of Lead in Distilleries.

DEAR SIR,

London, 20 February, 1768.

I wrote you a few lines by Captain Falconer, and sent you Dr. Watson's new piece of Experiments in Inoculation, which I hope will be agreeable to you.

In yours of November 20th, you mention the lead in the worms of stills as a probable cause of the dry belly-ache among punch-drinkers in our West Indies.

* A physician in Philadelphia, and member of the American Philosophical Society. Editor.