The Sun.
London, England, 1858-11-24 00:00:00

FRENCH ACADEMY OF SCIENCES•

At the last sitting M. Pouillet announced that
the committee appointed at the request of the
Minister of Agriculture, Commerce, and Pilot,
Works, to examine certain important questions 'P',/
lating to the laws on weights and measures, has foil%
it,impossible to reply to them, without undertaking,
series of experiments which will require much Oa,'
M. Pouillet, therefore, requested the AcadonYti,
inform the Minister of this inevitable delay.
Despretz communicated a long account of a series
of experiments he had been carrying on since Olaf
1857, in order to ascertain whether the chenu,,,.
substances hitherto looked upon as elements
simple bodies were really such or not. Chemists 4
accustomed to the almost daily occurrence of t"
most unlooked-for and surprising decompositien_l'
were generally imbued with a kind of sceptics
r
as regarded the undecomposable nature of cern
bodies. In 1807 Sir Humphrey Davy express!eo
an opinion that metals and other simple bocil
were mere compounds of an unknown base andf.
a substance forming a constituent of hydrogel',l
Gay-Lussac and Thenard regarded potassium a.n,h
sodium as a combiration of their alkalies NO4
hydrogen. In 1847, Gerhardt declared that
simple nature of the elements was not mathen!'e
tically demonstrated, and that science might sni'd
day succeed in decomposing sulphur, carbon, an
the metals. In 1857, M. Dumas, in a Pape
addressed to the Academy, admitted the existence.
of two conflicting opinions, one regarding the 611 b
stance called elements of simple bodies, the other'
on the contrary, considering them as resulting
from a single substance ; hydrogen, fcr instance,'
condensed to a degree varying according to the
nature of the different substances. The latter byPuit
thesis originated with Dr. Prout, who supposes
metal, for example, to be neither more nor lea
than hydrogen, or a still lighter gas, reduced t° a
_,
solid state by condensation. In order to test these
strange opinions, M. Despretz has subjected Or
per, lead, zinc, &c., to very high temperatures;
and decomposed their salts in various ways, alwal
obtaining the said metals in their natural state,'
whence he concludes that they are real elemenr;
having different properties, and not produced
the condensation of any gas. M. Encke sem
in a long communication on the comet whichto
bears his name, with numerous tables tending
.0
show the diminution of time observable ill ia
periodical reappearance. Mr. Encke first observe
it in 1819, but M. Olbers had since shown that :l
had been accidentally observed twice in 1786 byd
MM. Mechain and Messier, and that the comet
1795 also was no other than M. Eneke's. Taking
all these facts together, and calculating the perinl'ile
of reappearance, M. Encke now shows that t,
time of the comet's revolution, which was 1,212'.3
days in 1786-95, has fallen to 1,210.57 days
1855-58, being a loss of 2.06 days in the course '3,
73 years. This diminution M. Encke explains 11
a new hypothesis, viz., the resistance of a mediu'i
diffused throughout space. Dr. Bouchet present
a statistical table from which he deduces that &Li-
-1826 to 1840 the deaths by croup were 2,87:
and from 1840 to 1856 they amounted to 5,92' '
and that out of 388 operations of tracheotoinif
there were only 42 cures, showing a mortality ee
90 per cent. Dr. Dufraysse communicated a case
of asphyxia in a newly-born infant, the life
,°t
which he saved by introducing a tube into 0
larynx after Dr. Bouchet's method.