Paris, March 22, 1802.

As to the mechanical arts, if you are desirous to view some of the modern improvements and inventions in that line, you must accompany me to the Rue St. Martin, where, in the ci-devant priory, is an establishment of recent date, entitled the

CONSERVATORY OF ARTS AND TRADES.

Here is a numerous collection of machines of every description employed in the mechanical arts. Among these is the belier hydraulique, newly invented by MONTGOLFIER, by means of which a stream of water, having a few feet of declivity, can be raised to the top of a house by a single valve or sucker, so disposed as to open, to admit the water, and shut, when it is to be raised by compression. By increasing the compression, it can be raised to 1000 feet, and may be carried to a much greater elevation. The commissioners appointed by the Institute to examine this machine, reported that it was new, very simple, very ingenious, and might be extremely useful in turning to account little streams of water for the purposes of agriculture, manufactories, &c.

This reminds me of another singular hydraulic machine, of which I have been informed by a person who attended a trial made of it not long since in Paris.

A basin placed at the height of twenty feet, was filled with water, the fall of which set in motion several wheels and pumps that raised the water again into the basin. The machine was fixed in a place, glazed on all sides, and locked by three different keys. It kept in play for thirty-two days, without the smallest interruption; but the air, the heat, and the wood of the machine, having undoubtedly diminished the water, it no longer ascended into the basin. Till the thirty-second day, many persons imagined that the perpetual motion had been discovered. However, this machine was extremely light, well combined, and very simple in its construction. I ought to observe that it neither acted by springs nor counterpoise; all its powers proceeding from the fall of the water.

The conservatory also contains several models of curious buildings, too numerous to mention.

The mechanical arts in France appear to have experienced more or less the impulse given to the sciences towards the close of the eighteenth century. While calamities oppressed this country, and commerce was suspended, the inventive and fertile genius of the French was not dormant.

The clothiers have introduced woollen articles manufactured on a new plan; and their fine broad cloths and kerseymeres have attained great perfection. The introduction of the Spanish merinos into France has already produced in her wools a considerable amelioration.

Like a phoenix, Lyons is reviving from its ashes, and its silks now surpass, if possible, their former magnificence. Brocaded silk is at present made in a loom worked by one man only, in lieu of two, which the manufacture of that article hitherto demanded. Another new invention is a knitting-loom, by means of which 400 threads are interwoven with the greatest exactness, by merely turning a winch.

The cotton manufactures are much improved, and the manufactories in that line are daily increasing in number and perfection. A new spinning-machine has produced here, I am told, 160,000 ells in length out of a pound of cotton. The fly-shuttle is now introduced into most of the manufactories in this country, and 25 pieces of narrow goods are thus made at once by a single workman. In adopting ARKWRIGHT'S system, the French have applied it to small machines, which occupy no more room than a common spinning-wheel.

Among other branches in which the French mechanics have particularly distinguished themselves, since the revolution, is the making of astronomical and philosophical instruments.

All the machines used here in coining have also been modified and improved. By one of these, the piece is struck at the same time on the edge and on the flat side in so perfect a manner, that the money thus coined cannot he counterfeited.

I have already mentioned the invention of a composition which supplies the place of black lead for pencils, and the discovery of a new and very expeditious method of tanning leather.

New species of earthen-ware have been invented, and those already known have received considerable improvement.

Chemists have put the manufacturers in possession of new means of decomposing and recomposing substances. Muriat of tin is now made here with such economy, that it is reduced to one-eighth of its former price. This salt is daily used in dying and in the manufacture of printed calicoes. Carbonates of strontia and of baryt, obtained by a new process, will shortly be sold in Paris at 3 francs the kilogramme. This discovery is expected to have a great influence on several important arts, such as the manufacture of glass, of soap, &c.

Articles of furniture, jewellery, and every branch dependent on design, are now remarkable for a purer taste than that which they formerly exhibited.

Indeed, the characteristic difference of the present state of French industry, and that in which it was before the revolution, is that most of the proprietors of the manufactories have received a scientific education. At that time, many of them were strangers to the principles applicable to the processes of their art; and, in this respect, they lay at the mercy of the routine, ignorance, and caprice of their workmen. At present, the happy effects of instruction, more widely-diffused, begin to be felt, and, in proportion as it is extended, it excites a spirit of emulation which promises no small advantage to French commerce.