It is a long time, my dear Friend, since I have had the Pleasure of writing to you. I have postpon'd 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 & 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 always found so much Pleasure & Instruction, I now force myself to write, & I fancy this Letter will be long.
I have now before me your several Favours of Dec. 5. 1780 Feb. 7. April 7. May 23. & Aug. 29. 1781. I was glad to find by the first, that you enjoy'd a good State of Health, and that you had Leisure to pursue your Philosophical Enquiries. I wish you that continued Success which so much Industry, Sagacity & Exactness in making Experiments, have a Right to expect. You will have much Pleasure immediate by that Success, & in time great Reputation. But for the present, the Reputation will be given grudgingly & in as small a Quantity as possible, mix'd too with some Mortification. One would think that a Man so labouring 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 tho' 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, & being defeated there, they finally dispute his Right to them, and would give the Credit of them to a Man that liv'd 3000 Years ago, or at 3000 Leagues distance, rather than to a Neighbour or even a Friend. Go on, however, & never be discouraged. Others have met with the same Treatment before you, and will after you. And whatever some may think & 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 is possible, that in dipping them into the Wax & taking them out suddenly, the Metal which attracts Heat most readily, may chill & draw out with it a thicker Coat of Wax; and this thicker Coat might in the Progress of the Experiment, be longer in 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 dipt the Ends was not stagnant but in Motion, the Experiment would be more compleat: because the Wire wch. 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 Oil as a Conductor of Heat, that which is already cooled interfering between the hotter Oil & the Wire.— In reversing the Experiment also, to try which of the Metals cools the fastest, I think the Wires should be dipt 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 & 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 surprized that the Progress of the Heat seems to have no Connection with the Gravity or the Levity of the Metals.—
Those whom I have heard speak of your Book, speak well of it. But I think it has not been so much talkd of as might have been expected. This however is a Matter that is subject to accidents. The Death of a Prince, a Battle, or any other important Event happening just on the Publication of a new Book, tho' a very good one, occasion it to be little spoken of, and for sometime almost forgotten. We Printers & Booksellers are well acquainted with this.
You ask for News from America, and particularly what Effects attended the Defection of Arnold, and what were his Motives. He tried to draw others after him, but in vain; not a Man followed him. We discover'd his Motive by an intercepted Letter. It was a Bribe of five thousand Pounds Sterling. This he received in Bills of Exchange on London, where the Money was put into the Funds on his Account. He lives cover'd with Infamy, and despis'd even by those who expected to be serv'd by his Treachery. You will see by a German Almanack which I send you, how his Effigies was treated at Philadelphia. And since you ask for American Newspapers, I will send you some German Ones. We have three in that Language published Weekly at Philadelphia and Germantown, by which you may judge that the People with us who speak it are very numerous; and now that England can no longer monopolize our Commerce, the ancient Connections of those People with their Mother Country will be a means of opening a considerable American Trade with Germany by the North Seas, & the Mediterranean.
Never were Wars more unjustly and causelessly begun than those England is now engag'd in with your Country & mine. If she persists in them she is ruined; as she deserves to be. These Wars were evidently Wars of Rapine; they had no Provocation but the Hopes of Plunder. I think you us'd to have a better Opinion of that Nation than it deserv'd. It is extremely corrupted.
Mr. le Begue de Presle is much out of Town, so that I wish you had among the French a Correspondent, who resides constantly at Paris. I imagine M. le Roy would suit you. Tho' M. de Presle I believe will do what he can about your Publications. I shall be glad to see your Piece on the Electrophore when it is printed in English or French. I do not so easily read the German.—
I have never received a Line from Mr Wharton since his Arrival in America, and know nothing of his Affairs. I have desired Dr Bancroft who corresponds with him, to write to you about him.