1824. ] 
experiments for the purpose of demon- 
strating the point. A patient having under- 
gone the operation of brochotomy, the air 
which was’ expired’ from’ tle wound being 
passed “through ‘a ‘glass tube deposited 
aqueous vapour, not only on the inner sur- 
face of thé tube, but also on a glass held at 
the distance of four inches from its extre- 
mity. ‘Hence these gentlemen’ conclude, 
that, aqueous vapour is evolved from the 
whole surface of the respiratory organs, that 
it immediately issues from the \ mucous 
membrane lining these organs—that all the 
oxygen employed’ in ‘respiration’ goes to 
form carbonic acid gas, and that the animal 
heat is occasioned by the combination of 
oxygen with the carbon existing in the 
bleod, which heat is cemmunicated to the 
whole system by means of’ the arteries, 
while the lungs eject the carbonic acid in 
the act of respiration. 
Test for Nitrous Ovide.—Dr. Henry, of 
Manchester, recommends the following test : 
A given volume of the nitrous oxide is to 
be exploded with a slight excess of carbonic 
oxide of known purity, as 100 measures of 
the former to 110 of the latter. Now as 
each volume of pure nitrous oxide gives, 
under these circumstances, an equal volume 
of carbonic acid, we may impute whatever 
earbonie acid is deficient ef that proportion 
to the mixture of so much nitrogen with 
the nitrous oxide. If e.g. using an excess 
of carbonic oxide, there results from 100 
measures ‘of nitrous oxide, only 95 of car- 
bonie acid, we may safely consider the ni- 
trous oxide, to’ be’ contaminated with five 
per cent. of nitrogen gas. Any nitrous gas 
may be previously separated by a solution 
of green sulphate of iron. 
Gasious matter evolved by plants. —The 
Journal de Pharmacie acquaints us that M. 
Chevallier has’ discovered a very curious 
fact, that ammonia is copiously disengaged 
in a free state by the process of vegetation; 
and that, in’ conjunction with M. Boulay, 
he has also ascertained that nearly every 
species: of ‘aromatic flowers spontaneously 
disengages ammonia in the act of vegetation. 
Surely this fact-cannot be considered a new 
discovery, except' by the abovemention- 
ed chemists themselves! The aroma of 
plants is well known to be peculiar essen- 
tial oils, held'in’suspension in volatile alkali 
or gaseous'‘ammonia. Tlie taste of the 
minor’ French chemists of the present day 
seems' to be peculiarly directed to what may 
be termed. the re-analysis of well analyzed 
substances, apparently with the view of an- 
nouneing something new, if not always 
useful) We have considerable doubt as to 
the aggregate’ benefits resulting from the 
pharmacoperia being loaded with the minute 
subdivisions, ‘in® which our ingenious neigh- 
bours ‘hive’ recently exhibited the different 
varietiés of vegetable: poisons: 
Minerils produced artificially:—Ithasbeen 
very often observed that the analysés of mine 
rals are of comparatively little value, as long us 
Spirit of Phitosophical Discovery. 
339 
we are not capable of reproducing by com- 
position what had been dissolved. Professor 
Mitsehterlich has accomplished this impor- 
tant object... We have been gratified by the 
sight of beautiful and, well-defined, crystals 
of greyish white pyroxine, which had been 
obtained by. mixing, the constituent, parts 
indicated, by analyses, in, the mecessary. pro- 
protion, and exposing this mixture. to the 
high’ degree of heat of the porcelain fur- 
nages at Sevres in France, By this means 
Professor, Mitschterlich. has succeeded, in 
obtaining several species: that, occur in na- 
ture. He has likewise observed among the 
different kinds, of slags, more, than. forty 
species in a crystallized state, particularly 
of such minerals, as are. found in primitive 
rocks, but also of a good many, others 
which haye not hitherto been. obseryed. 
—Dr,. Brewster's Journal. ’ 
Thermometers. —In Von. Zach's... Corr. 
Astr., No. 5, a set of interesting observa- 
tions appear on the comparative. expansion 
of mercury and spirit of wine as. applicable 
to the thermometer. . The observations 
were made by a very accurate observer, 
M. Flanguergues, of Viviers; with great 
care, and are therefore entitled to consider- 
able confidence. The spirit. thermometer 
was an excellent one, made under the in- 
spection of Reaumur. himself ; and the mer- 
curial thermometers, of which there were 
several, were constructed by the best artists. 
They were all similarly divided, according 
to the octogenial scale of Reaumur; and 
the ‘experiments were each frequently. re-_ 
peated, in order to obtain an average or cor-~ 
rect result. - 
The effect produced by «the, following 
freezing mixtures on each thermometer, was: 
Two parts of pounded 
ice, and one part by Spit Mercury 
weight of muriate of 
soda, sunk the...... —17°.4 —16°.6 
Two of ice and one of 
muriate of ammonia... —12,7 —12, 4 
Two of ice and one of : 
crystallized sugar.... — 5, — 4.9 
Two of ice and one of 
DIVE) 0b Ss - coeeeinale eeerde Oy hem) O42 
Melting ice.......4.-.- 0, 0. 
A well, 34. feet. deep, 
(mean of six years ob- 
seryation)....e.-.--+-10, 47; +. 9.64 
Ascellar tise tyadasheyodeai'S 12.7. 
The human bedy....... 32. .7 29.8 
Fusion. of , yellow) wax), .56..25 49.6 
Bojling-alcohol, density ; 
851. Barom. at 28in, 75, 6 63.5 
Boiling mixture of three, 
parts,.of alcohol. and # 
one of ‘water, the mix- ; fs datrk« 
ture used for .Reau- 5...) «yh fsb 
:mur’s thermometer, ., iy atatifier of 
ogenerallyiss serensieb old BO. (66.8. 
hoKrom the above discordance, it. seems no 
longerdoubtful,that jalcohol and mercury 
are: not, equally, expanded and contracted, 
by equal: increments or decrements of ca- 
2X 2 loric. 
