Paris, October 23, 1801.

Since my arrival, I have been so much engaged in paying and receiving visits, that I really have not yet been able to take even a hasty view of any of the grand sights introduced here since the revolution,

On Wednesday I dined with M. S----i, whose new 8vo edition of Buffon proceeds, I find, with becoming spirit. It is quite a journey to his residence; for he lives in one of the most retired quarters of Paris, However, I had no reason to repine at the distance, as the party was exceedingly cheerful. Naturalists and literati were not wanting.

Egypt was a subject that engrossed much of the conversation: it was mentioned as a matter of regret that, during the dominion of the French in that country, curiosity had not prompted the Institute, established at Cairo, to open one of the pyramids, with a view of ascertaining the object of the erection of those vast masses. At the desert, we had luscious grapes as large as damsons, in bunches of from three to five pounds in weight. They were of the species of the famous chasselas de Fontainebleau, which are said to have sprung from a stock of vine-plants, imported by Francis I. from the island of Cyprus. These did not come from that town, but grew against the naked wall in S----i's garden. From this you may form a judgment of the climate of Paris.

The persons with whom I have had any correspondence, respecting literature, vie with each other in shewing me every mark of cordial hospitality; and those to whom I have been introduced, are by no means backward in friendly attention. All the lovers of science here seem to rejoice that the communication, which has been so long interrupted between the two countries, promises to be shortly re-opened.

After dining yesterday with Mr. M----y, the British minister, in company with Mr. D----n, the member for Ilchester, we all three went to an exhibition almost facing Mr. M----y's residence in the Rue St. Dominique. This was the third time of its being open to the public. As it is of a novel kind, some account of it may not be uninteresting. In French, it is denominated

THERMOLAMPES,
or stoves which afford heat and light on an economical plan.

The author of this invention, for which a patent has been obtained, is M. LEBON, an engineer of bridges and highways. The place of exhibition was the ground floor of one of the large hotels in the Faubourg St. Germain, on which was a suite of rooms, extremely favourable for displaying the effect of this new method of lighting and warming apartments.

In lieu of fire or candle, on the chimney stood a large crystal globe, in which appeared a bright and clear flame diffusing a very agreeable heat; and on different pieces of furniture were placed candlesticks with metal candles, from the top of each of which issued a steady light, like that of a lamp burning with spirits of wine. These different receptacles were supplied with inflammable gas by means of tubes communicating with an apparatus underneath. By this contrivance, in short, all the apartments were warmed very comfortably, and illuminated in a brilliant manner.

On consulting M. LEBON, he communicated to me the following observations: "You may have remarked," said he, "in sitting before a fire, that wood sometimes burns without flame, but with much smoke, and then you experience little heat, sometimes with flame, but with little smoke, and then you find much warmth. You may have remarked too, that ill-made charcoal emits smoke; it is, on that account, susceptible of flaming again; and the characteristic difference between wood and charcoal is, that the latter has lost, together with its smoke, the principle and aliment of flame, without which you obtain but little heat. Experience next informs us, that this portion of smoke, the aliment of flame, is not an oily vapour condensable by cooling, but a gas, a permanent air, which may be washed, purified, conducted, distributed, and afterwards turned into flame at any distance from the hearth.

"It is almost needless," continued he, "to point out the formation of verdigrise, white lead, and a quantity of other operations, in which acetous acid is employed. I shall only remark that it is this pyroligneous acid which penetrates smoked meat and fish, that it has an effect on leather which it hardens, and that thermolampes are likely to render tanning-mills unnecessary, by furnishing the tan without further trouble. But to return to the aËriform principle.

"This aliment of flame is deprived of those humid vapours, so perceptible and so disagreeable to the organs of sight and smell. Purified to a perfect transparency, it floats in the state of cold air, and suffers itself to be directed by the smallest and most fragil pipes. Chimnies of an inch square, made in the thickness of the plaster of ceilings or walls, tubes even of gummed silk would answer this purpose. The end alone of the tube, which, by bringing the inflammable gas into contact with the atmospheric air, allows it to catch fire, and on which the flame reposes, ought to be of metal.

"By a distribution so easy to be established, a single stove may supply the place of all the chimnies of a house. Every where inflammable air is ready to diffuse immediately heat and light of the most glowing or most mild nature, simultaneously or separately, according to your wishes. In the twinkling of an eye, you may conduct the flame from one room to another; an advantage equally convenient and economical, and which can never be obtained with our common stoves and chimnies. No sparks, no charcoal, no soot, to trouble you; no ashes, no wood, to soil your apartments. By night, as well as by day, you can have a fire in your room, without a servant being obliged to look after it. Nothing in the thermolampes, not even the smallest portion of inflammable air, can escape combustion; while in our chimnies, torrents evaporate, and even carry off with them the greater part of the heat produced.

"The advantage of being able to purify and proportion, in some measure, the principles of the gas which feeds the flame is," said M. LEBON, "set forth in the clearest manner. But this flame is so subjected to our caprice, that even to tranquilize the imagination, it suffers itself to be confined in a crystal globe, which is never tarnished, and thus presents a filter pervious to light and heat. A part of the tube that conducts the inflammable air, carries off, out of doors, the produce of this combustion, which, nevertheless, according to the experiments of modern chymists, can scarcely be any thing more than an aqueous vapour.

"Who cannot but be fond of having recourse to a flame so subservient? It will dress your victuals, which, as well as your cooks, will not be exposed to the vapour of charcoal; it will warm again those dishes on your table; dry your linen; heat your oven, and the water for your baths or your washing, with every economical advantage that can be wished. No moist or black vapours; no ashes, no breaze, to make a dirt, or oppose the communication of heat; no useless loss of caloric; you may, by shutting an opening, which is no longer necessary for placing the wood in your oven, compress and coerce the torrents of heat that were escaping from it.

"It may easily be conceived, that an inflammable principle so docile and so active may be made to yield the most magnificent illuminations. Streams of fire finely drawn out, the duration, colour, and form of which may be varied at pleasure, the motion of suns and turning-columns, must produce an effect no less agreeable than brilliant." Indeed, this effect was exhibited on the garden faÇade of M. LEBON'S residence.

"Wood," concluded he, "yields in condensable vapours two thirds of its weight; those vapours may therefore be employed to produce the effects of our steam-engines, and it is needless to borrow this succour from foreign water."

P. S.. On the 1st of last VendÉmiaire, (23rd of September), the government presented to the Chief Consul a sword, whose hilt was adorned with fourteen diamonds, the largest of which, called the Regent, from its having been purchased by the Duke of Orleans, when Regent, weighs 184 carats. This is the celebrated Pitt diamond, of which we have heard so much: but its weight is exceeded by that of the diamond purchased by the late empress of Russia, which weighs 194 carats; not to speak of the more famous diamond, in possession of the Great Mogul, which is said to weigh 280 carats.