I have duly received your favor of April 10. by Mr. Mazzei. You therein speak of a new method of raising water by steam which you suppose will come into general use. I know of no new method of that kind and suppose (as you say that the account you have received of it is very imperfect) that some person has represented to you as new a fire engine erected at Paris and which supplies the greater part of the town with water. But this is nothing more than the fire engine you have seen described in the books of Hydraulics and particularly in the dictionary of arts and sciences published in 8vo. by Owen, the idea of which was first taken from Papin’s digester. It would have been better called the Steam engine. The force of the steam of water you know is immense. In this engine it is made to exert itself towards the working of pumps. That of Paris is I believe the largest known, raising 400,000 cubic feet (French) of water in 24 hours: or rather, I should have said, those of Paris, for there are two under one roof, each raising that quantity.

The Abbé Rochon not living at Paris, I have not had an opportunity of seeing him and of asking him the questions you desire relative to the Chrystal of which I wrote you. I shall avail myself of the earliest opportunity I can of doing it.—I shall chearfully execute your commands as to the Encyclopedie when I receive them. The price will be only 30. guineas. About half the work is out. The volumes of your Buffon which are spoiled can be replaced here.

I expect that this letter will be carried by the Mr. Fitzhughs in a ship from Havre to Portsmouth. I have therefore sent to Havre some books which I expected would be acceptable to you. These are the Bibliotheque physico-œconomique which will give you most of the late improvements in the arts; the Connoissance des tems for 1786. and 1787. which is as late as they are published, and some peices on air and fire wherein you will find all the discoveries hitherto made on these subjects. These books are made into a packet with your address on them and are put into a trunk wherein is a small packet for Mr. Wythe, another for Mr. Page, and a parcel of books without direction for Peter Carr. I have taken the liberty of directing the trunk to you as the surest means of it’s getting safe. I pay the freight of it here, so that there will be no new demands but for the transportation from the ships side to Wmsburg. which I will pray you to pay, and as much the greatest part is for my nephew I will take care to repay it to you.

In the last volume of the Connoissance des tems you will find the tables for the planet Herschel. It is a curious circumstance that this planet was seen 30 years ago by Mayer, and supposed by him to be a fixed star. He accordingly determined a place for it in his catalogue of the Zodiacal stars, making it the 964th. of that catalogue. Bode of Berlin observed in 1781 that this star was missing. Subsequent calculations of the motion of the planet Herschel shew that it must have been, at the time of Mayer’s observation, where he had placed his 964th. star.

Herschell has pushed his discoveries of double stars now to upwards of 900. being twice the number of those communicated in the Philosophical transactions. You have probably seen that a Mr. Pigott had discovered periodical variations of light in the star Algol. He has observed the same in the η of Antinous, and makes the period of variation 7D. 4H. 30’, the duration of the increase 63.H. and of the decrease 36H. What are we to conclude from this? That there are suns which have their orbits of revolution too? But this would suppose a wonderful harmony in their planets, and present a new scene where the attracting powers should be without and not within the orbit. The motion of our sun would be a miniature of this. But this must be left to you Astronomers.

We were told some time ago of a cheap method of extricating inflammable air from pit-coal. This would facilitate the experiments with baloons. Two artists are employing themselves in the means of directing their course. They can ascend and descend at will without expending their gaz, and have been able to deflect from the course of the wind 45°.

I went sometime ago to see a machine which offers something new. A man had applied to a light boat a very large screw, the thread of which was a thin plate two feet broad applied by it’s edge spirally round a small axis. It somewhat resembled a bottle brush if you will suppose the hairs of the bottle brush joining together and forming a spiral plane. This, turned on it’s axis in the air, carried the vessel across the Seine. It is in fact a screw which takes hold of the air and draws itself along by it: losing indeed much of it’s effort by the yeilding nature of the body it lays hold of to pull itself on by. I think it may be applied in the water with much greater effect and to very useful purposes. Perhaps it may be used also for the baloon.

It is impossible but you must have heard long ago of the machine for copying letters at a single stroke, as we had received them in America before I left it. I have written a long letter to my nephew, in whose education I feel myself extremely interested. I shall rely much on your friendship for conducting him in the plan I mark out for him, and for guarding him against those shoals on which youth sometimes shipwreck. I trouble you to present to Mr. Wythe my affectionate remembrance of him and am with very great esteem Your friend & servant,