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JAMES MADISON, of William and Mary College.

Paris, October 2, 1785.

Dear Sir,

I have duly received your favor of April the 10th, 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 four hundred thousand cubic feet (French) of water, in twenty-four hours; or rather I should have said, those of Paris, for there are two under one roof, each raising that quantity.

The Abbe 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 crystal of which I wrote you. I shall avail myself of the earliest opportunity I can, of doing it. I shall cheerfully execute your commands as to the Encyclopédie, when I receive them. The price will be only thirty 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 Bibliothèque Physico-oeconomique, which will give you most of the late improvements in the arts; the Connoissance des Terns for 1786 and 1787, which is as late as they are published; and some pieces 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 its getting safe. I pay the freight of it here, so that there will be no new demands, but for the transportation from the ship’s side to Williamsburg, 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 Terns, you will find the tables for the planet Herschel. It is a curious circumstance, that this planet was seen thirty 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 show, that it must have been, at the time of Mayer’s observation, where he had placed his 964th star.

Herschel has pushed his discoveries of double stars, now, to upwards of nine hundred, 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 n of Antinous, and makes the period of variation seven days, four hours, and thirty minutes, the duration of the increase sixty-three hours, and of the decrease thirty-six hours. 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.

I went some time 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 its 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 its 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 its effort by the yielding 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 balloon.

It is impossible but you must have heard long ago of the machine for copying letters at a single stroke, as we had received it in America before I left there. 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, Dear Sir,

your friend and servant,

Th: Jefferson.