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It is said that this malady originated in the ill-judged curiosity of some country people, who, at Candlemas last, opened the graves of some persons, who had died of the plague in the preceding century, and whe had been buried in the Moss of Arnhall. The circumstances which have happened in the family of Mr. Robert Aikenhead are singularly unfortunate; about the middle of last month he took the infection, which was communicated to the rest of his family, consisting of nine persons; two of whom, together with himself, are dead, and the others not out of danger."



Paris, 23 August, 1781.


I have presented to the Royal Society of Medicine, conformably to your intentions, the memoir by Mr. Small translated from the English, upon the method of ventilating the interior of hospitals, together with your letter which accompanied it.

The Society has attended to the reading of both of these pieces. Your letter contains some very important observations, which are worth preserving, upon the time necessary for the decay of bodies buried in the ground. The Society is much flattered that you have approved its report upon the dangers of interment. You have requested some copies of it, which I have the honor to send you. The Society desired to hear the entire reading of the observations of Mr. Small, and was highly pleased with them. We have there found your great principles of physics. A detailed report will be made upon this subject, in

which the most ample justice will be done to the author. The Society begs you to accept their thanks, and to communicate them to Mr. Small, whose paper we have listened to with so much pleasure. I am, Sir, &c.,



On Conductors of Heat.

Passy, 2 Octobe- 1781.

It is a long time, my dear friend, since I have had the pleasure of writing to you. I have postponed it too often from a desire of writing a good deal on various subjects, which I could not find sufficient time to think of properly. Your experiments on the conducting of heat was one subject; the finishing my remarks on the stroke of lightning in Italy* was another. Then I was taken ill with a severe fit of the gout soon after you left us, which held me near three months, and put my business and correspondence so far behind-hand, that I was long in getting it up again. Add to this, that I find indolence increases with age, and that I have not near the activity I formerly had. But I cannot afford to lose your correspondence, in which I have always found so much pleasure and instruction. I now force myself to write, and I fancy this letter will be long.

I have now before me your several favors of December 5th, 1780, February 7th, April 7th, May 23d, and August 29th, 1781. I was glad to find by the first, that you enjoyed a good state of health, and

* See An Attempt to explain the Effects of Lightning on the Steeple of a Church in Cremona; Vol. V. p. 467.

that you had leisure to pursue your philosophical inquiries. I wish you that continued success, which so much industry, sagacity, and exactness in making experiments, have a right to expect. You will have much immediate pleasure by that success, and in time. great reputation. But for the present the reputation will be given grudgingly, and in as small a quantity as possible, mixed too with some mortification. One would think that a man so laboring disinterestedly for the good of his fellow creatures, could not possibly by such means make himself enemies; but there are minds who cannot bear that another should distinguish himself even by greater usefulness; and though he demands no profit, nor any thing in return but the good will of those he is serving, they will endeavour to deprive him of that, first by disputing the truth of his experiments, then their utility; and, being defeated there, they finally dispute his right to them, and would give the credit of them to a man that lived three thousand years ago, or at three thousand leagues distance, rather than to a neighbour or even a friend. Go on, however, and never be discouraged. Others have met with the same treatment before you, and will after you. And, whatever some may think and say, it is worth while to do men good, for the selfsatisfaction one has in the reflection.

Your account of the experiments you made with the wires gave me a great deal of pleasure. I have shown it to several persons here, who think it exceedingly curious. If you should ever repeat those experiments, I wish your attention to one circumstance. I think it possible, that, in dipping them into the wax, and taking them out suddenly, the metal which attracts heat most readily may chill and draw out with it a thicker coat of wax; and this thicker coat might,

in the progress of the experiment, be longer melting. They should therefore be kept so long in the wax, as to be all well and equally heated. Perhaps you may thus find the progress of heat in the silver quicker and greater. I think, also, that, if the hot oil in which you dipped the ends was not stagnant, but in motion, the experiment would be more complete, because the wire which quickest diminishes the heat of the oil next to it, finds soonest the difficulty of getting more heat from the oil farther distant, which depends on the nature of the oil as a conductor of heat, that which is already cooled interfering between the hotter oil and the wire. In reversing the experiment also, to try which of the metals cools fastest, I think the wires should be dipped in running cold water; for, when stagnant, the hot wires, by communicating heat to the water that is near them, will make it less capable of receiving more heat; and, as the metals which communicate their heat most freely and readily will soonest warm the water round them, the operation of such metals may therefore soonest stop; not because they naturally longer withhold their heat, but because the water near them is not in a state to receive it. I do not know that these hints are founded; I suggest them only as meriting a little consideration. Every one is surprised that the progress of the heat seems to have no connexion with the grav ity or the levity of the metals.


An Account of Toads found enclosed in Solid Stone.

Ar Passy, near Paris, April 6th, 1782, being with M. de Chaumont, viewing his quarry, he mentioned to me, that the workmen had found a living toad shut up in the stone. On questioning one of them, he told us, they had found four in different cells which had no communication; that they were very lively and active when set at liberty; that there was in each cell some loose, soft, yellowish earth, which appeared to be very moist. We asked, if he could show us the parts of the stone that formed the cells. He said, No; for they were thrown among the rest of what was dug out, and he knew not where to find them. We asked, if there appeared any opening by which the animal could enter. He said, No. We asked, if, in the course of his business as a laborer in quarries, he had often met with the like. He said, Never before. We asked, if he could show us the toads. He said, he had thrown two of them up on a higher part of the quarry, but knew not what became of the others.

He then came up to the place where he had thrown the two, and, finding them, he took them by the foot, and threw them up to us, upon the ground where we stood. One of them was quite dead, and appeared very lean; the other was plump and still living. The part of the rock where they were found, is at least fifteen feet below its surface, and is a kind. of limestone. A part of it is filled with ancient seashells, and other marine substances. If these animals have remained in this confinement since the formation of the rock, they are probably some thousands of years old. We have put them in spirits of wine, to preserve their bodies a little longer. The

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