_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.