visible in England but when the atmosphere is pretty clear of clouds for the whole space between us and those regions; and therefore are seldom visible there. This extensive clearness may have been produced by a long continuance of northerly winds. When the winds have long continued in one quarter the return is often violent. Allowing the fact so repeatedly observed by Mr. Winn, perhaps this may account for the violence of the southerly winds that soon follow the appearance of the aurora on our coasts.

ON A NEW INVENTED STOVE.'

TO THE MARQUIS TURGOT.

Passy, 1st May, 1781.

I DID intend, when in London, to have published a pamphlet, describing the new stove you mention, and for that purpose had a plate engraved, of which I send you an impression. But I have since been too much engaged in affairs to execute that intention. Its principle is that of a siphon reversed, operating on air in a manner somewhat similar to the operation of the common siphon on water. The funnel of the chimney is the longer leg, the vase is the shorter: and, as in the common siphon, the weight of water in the longer leg is greater than that in the shorter leg; and thus in descending permits the water in the shorter leg to rise, by the pressure of the atmosphere. So in this aerial siphon, the levity of the air in the longer leg being greater than that in the shorter, it rises and permits the pressure of the atmosphere to force that in the shorter to descend. This causes the smoke to descend also, and in passing through burning coals, it is kindled into flame, thereby heating more the passages in the iron box whereon the vase which contains the coals is placed; and retarding at the same time the consumption of the coals. On the left hand of the engraving you see the machine put together and placed in a niche built for it in a common chimney. On the right hand the parts (except the vase) are shown separately. If you should desire a more particular explanation, I will give it to you viva voce, whenever you please. I think with you that

See Plate IV.

it is capable of being used to advantage in our kitchens, if one could overcome the repugnance of cooks to the using of new instruments and new methods.

I RECEIVED the letter you some time since did me the honor of writing to me, accompanied with a number of the pieces that were distributed at the last public meeting of the Royal Society of Medicine. I shall take care to forward them to different parts of America, as desired. Be pleased to present my thanks to the society for the copy sent me of the curious and useful reports relating to the sepulture in the island of Malta. I should be glad of another copy, if it can be spared, being desirous of sending one to each of the philosophical societies in America.

With respect to the length of time during which the power of infection may be contained in dead bodies, which is considered in that report, I would mention to you three facts, which, though not all of equal importance or weight, yet methinks it may be well to preserve a memorandum of them, that such observations may be made when occasion offers, as are proper to confirm or invalidate them.

While I resided in England, I read in a newspaper, that in a country village at the funeral of a woman whose husband had died of the small-pox 30 years before, and whose grave was dug so as to place her by his side, the neighbors attending the funeral were offended with the smell arising out of the grave, occasioned by a breach in the husband's old coffin, and 25 of them were in a few days taken ill with that distemper, which before was not in that village or its neighborhood, nor had been for the number of years above mentioned.

About the years 1763 or 1764, several physicians of London, who had been present from curiosity at the dissection of an Egyptian mummy, were soon after taken ill of a malignant fever, of which they died. Opinions were divided

on this question. It was thought by some that the fever was caused by infection from the mummy; in which case the disease it died of must have been embalmed as well as the body. Others who considered the length of time, at least 2000 years, since that body died, and also that the embalming must be rather supposed to destroy the power of infection, imagined the illness of these gentlemen must have had another original.

About the year 1773, the captain of a ship which had been at the island of Teneriffe, brought from thence the dried body of one of the ancient inhabitants of that island, which must have been at least 300 years old, that custom of drying the dead there having been so long discontinued. Two members of the Royal Society went to see that body. They were half an hour in a small close room with it, examining it very particularly. The next day they were both affected with a singularly violent cold,' attended with uncommon circumstances, which continued a long time. On comparing together the particulars of their disorder, they agreed in suspecting that possibly some effluvia from the body might have been the occasion of that disorder in them both: perhaps they were mistaken. But as we do not yet know with certainty how long the power of infection may in some bodies be retained, it seems well in such cases to be cautious till farther light shall be obtained.

I wish it were in my power to contribute more essentially in advancing the good work the society are so laudably engaged in. Perhaps some useful hints may be extracted from the enclosed paper of Mr. Small's. It is submitted to your judgment; and if you should find any thing in it worthy of being communicated to the society, and of which extracts may be useful if printed in the memoirs, it will be a pleasure to me; who am, with great esteem and respect, sir, &c. B. FRANKLIN.

P. S. July 24. Since writing the above, I have met with the following article in the Courier de l'Europe of the 13th inst. viz.

Extrait d'une lettre d'Edimbourg, en date du 30 Juin. "J'apprends par une personne qui vient de Montrose, que la fièvre épidémique qui s'est manifestée il y a quelque tems dans le Méarns, désole

' Cold is a general name given by the English to all sorts of rheums and catarrhs.
2 See OF VENTILATION-Writings, Part IV.

encore aujourd'hui ce voisinage avec tant de violence qu'un de ses amis a été invité à assister à 15 enterremens dans un seul jour. On dit que cette maladie doit son origine à la folle curiosité de quelques paysans, qui, à la Chandeleur dernière, exhumèrent quelques personnes mortes de la peste dans le siècle précédent, et qu'on avoit enterrées dans le Moss de Arnhall. Ce qui est arrivé à la famille de M. Robert Aikenhead est singulièrement malheureux : vers le milieu du mois dernier il a été attaqué de cette contagion, et elle s'est communiquée au reste de sa famille consistant en neuf personnes, dont deux sont mortes ainsi que lui, et le reste n'est pas sans danger.”

[Translation.]

Extract of a letter from Edinburgh, dated June 30.

"I understand by a person just returned from Montrose, that the epidemic fever which has made its appearance in the county of Mearns, ravages that neighborhood with such violence, that one of his friends was invited to attend fifteen funerals on the same day. It is said that this malady originates 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 who 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."

ON CONDUCTORS OF HEAT, &c.

To DR. INGENHAUSZ.

Passy, Oct. 2, 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 behindhand, 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 Dec. 5, 1780, Feb. 7, April 7, May 23, and Aug. 29, 1781. I was glad to find by the first, that you enjoyed a good state of health, and 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 á 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 endeavor 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 3000 years ago, or at 3000 leagues distance, rather than to a neighbor 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 self-satisfaction 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 See-Attempt to explain the effects of Lightning on the Steeple of Cremona. WRITINGS. Part IV.

3