Your favour of the 10th. Dec. came to hand about a fortnight after it’s date. It has occasioned me to reflect a little more attentively on Buffon’s central heat than I did in the moment of our conversation and to form an opinion different from what I then expressed. The term ‘central heat’ does of itself give us a false idea of Buffon’s hypothesis. If it meant a heat lodged in the center of the earth and diffusing it’s warmth from thence to the extremities, then certainly it would be less in proportion to the distance from that center, and of course less under the equator than the poles, on high mountains than in deep vallies. But Buffon’s theory is that this earth was once in a state of hot fusion, and that it has been, and still continues to be, cooling. What is the course of this process? A heated body being surrounded by a colder one whether solid or fluid, the heat, which is itself a fluid, flows into the colder body equally from every point of the hotter. Hence if a heated spheriod of iron cools to a given degree, in a given space of time, an inch deep from it’s surface, in one point, it has in the same time done the same in any and every other point. In a given time more, it will be cooled all round to double that depth, so that it will always be equally cooled at equal depths from the surface. This would be the case of Buffon’s earth if it were a smooth figure without unevennesses. But it has mountains and vallies. The tops of mountains will cool to greater depths in the same time than the sides of mountains and than plains in proportion as the line a. b. is longer than a.c. or d.e. or f. g. In the valley the line h.i. or depth of the same temperature will be the same as on a plain.

This however is very different from Buffon’s opinion. He sais that the earth being thinnest at the poles will cool sooner there than under the equator where it is thicker. If my idea of the process of cooling be right his is wrong and his whole theory in the Epochs of nature is overset.

The note which I delivered you contained an acknowlegement of my having borrowed from you a draught for 333⅓ dollars and a promise to repay it on demand. This was exclusive of what I had borrowed in Philadelphia.

We have never yet had more than 7. states, and very seldom that, as Maryland is scarcely ever present, and we are now without a hope of it’s attending till February. Consequently having six states only, we do nothing. Expresses and letters are gone forth to hasten on the absent states that we may have 9. for a ratification of the definitive treaty. Jersey perhaps may come in, and if Beresford will not come to Congress, Congress must go to him to do this one act. Even now it is full late. The critical situation in which we are like to be gave birth to an idea that 7. might ratify. But it could not be supported. I will give you a further account of this when it shall be finally settled.

The letters of our ministers inform us that the two empires have formed a league defensive against Christian powers and offensive against the Turks. When announced by the Empress to the K. of Prussia he answered that he was very sensible on it as one is when informed of important things. France answered in a higher tone and offered to mediate. If Prussia will join France perhaps it may prevent the war: if he does not, it will be bold for France alone to take the aid of the Turks on herself. Ireland is likely to find employment for England. The United Netherlands are in high fermentation. The people now marshall themselves in arms and exercise regularly under the banners of their towns. Their object is to reduce the powers of the Stadtholder.

I have forwarded your letter to Mrs. House. Mrs. Trist I expect left Philadelphia about the 18th. of Dec. for Pittsburgh. I had a letter from her in which she complained of your not having written and desired me to mention it to you. I made your excuse on the good grounds of the delays you must have experienced on your journey and your distance from the post road: but I am afraid she was gone before my letter reached Philadelphia. I have had very ill health since I have been here and am getting rather lower than otherwise. I wish you every felicity and am with sincere affection Your friend & servt.,