1823.] « 
lished, in the same year, by M. Pouillet. 
If the line is a circumference of a circle, 
we then find one of the results of the 
experiments of Messrs: Gay-Lussac 
and Welter, on a steel ring magnetised, 
by the process of M. Arago. If the line 
of the centres is only a curve; with two 
branches symmetrical, with respect to a 
plane passing through the conductor, 
the analysis leads to a result confirmed 
by receut experiments. 
The second circular memoir is that of 
M. F. Savary; some account of it bas 
already beech given in the Revue En- 
eyclopedique. 
Never was any discovery prosecuted 
with more zeal and success than that 
of Cirstedt, on the analogy between the 
electric and magnetic fluids. Three 
years have hardly elapsed, and the 
science has already arrived at certain 
theories, founded on facts, numerous 
aud well analysed ; also, at methods of 
calculation which would, alone, produce 
new discoveries. 
. While the knowledge relative to elec- 
tricity and magnetism is acquiring 
daily accessions, the science of light 
and optics is advancing with rapid 
steps. M. Fresnel has presented several 
memoirs, the object of which is to ex- 
press the general laws of doubie re- 
fraction; also to discover the laws of 
a new kind of polarisation, to which he 
has given the name of circular polari- 
sation ; also, to prove directly, that glass 
compressed, causes light to undergo a 
double refraction ; and lastly, to examine 
the law of modification impressed by 
a total reflection on polarised light. 
These researches are connected with 
the theoretic nofions that M. Fresnel, 
and seyernl other writers on’ pliysics, 
have adopted, respecting the nature, of 
Jight. They consider its action as 
operated by vibrations extremely ra- 
pid, propagated in elastic mediums. 
From this opinion not being generally 
admitted, some dissensions lave arisen 
in the republic of sciences, though, 
from habil, more peaceably disposed 
than that of letters. 
The minister of interior had desired 
the academy {to cxamine afresh the 
question of areometers, and compare 
the respective methods proposed, so as 
to determine with precision, by meats 
of that instrument, the specific weight 
of liquids. 
commission charged with this labour, 
has retraced some very accnrate expe- 
riments already made, by M. Gay- 
Lussac, therein completcly answering 
Montuy Maa, No. 387. 
Academy of Sciences. 
M. Arago, reporter to the” 
249 
the views of administration. M, Gay- 
Lussac has drawn up tables, that for 
science and minute detail become the 
surest guide that rulers can follow in 
the collection of the revenue. A’ me- 
moir of M. Francoeur, on’ this subject, 
and another by M. Benoit on areome- 
ters, have honourable mention in ‘the 
report of the commission. ‘The latter 
memoir may he considered as an ex- 
cellent chapter of a treatise on physics; 
but the author has not taken up the 
experimental part of the question. 
M. Despretz has applied himself to 
consider the conduetibility of bodies, 
tliat is, the greater or less facility with 
which heat penetrates them, and spreads 
through their interior.” He has found 
that, in their relation to this property, 
the following bodies or substances are 
in the order that experiment has ascer- 
tained, commencing with the highest 
degree; copper, iron, zinc, tin, lead, 
marble, poreclain, and brick-clay. ‘The 
report on this labour was drawn up by 
M. Fourier. The results obtained by 
M. Depretz are pronounced by the com- 
missaries to be every way worthy of the 
academy’s encouragement; and that the 
physical sciences, several arts, and the 
oeconomical processes, as to the distri- 
bution and use of fuel, would be bene- 
fited by their publication. 
Of three comets observed in 1822, 
the first was discovered by M. Gambart, 
to whom we owe, also, the observation 
f two others at Marseilles. MM. Pons 
was the first that discovered the other 
two. ‘Phe Revue has already noticed 
that comet whose revolution was deter- 
mined by M, Euke, and which has been 
designated as the comet of a short 
period; it will hereafter, no doubt, re-' 
ecive an appropriate name, like the 
other bodies of our system. 
M. Gambey presented to the Aca- 
demy two instruments, constracted on 
new principles, 1. A compass of decli- 
nation; and 2, an heliostaft. With re- 
spect to the invention and execution of 
astronomical itstruments, M.G. is, at 
present, the first artist in Europe. 
M. the Abbé Halma, translator of the 
Almagest, is now publishing a French 
translation of Ptolemy’s “ Manual 
Tables,” hereby rendering a new service 
to astronomy. He is also ‘prosecuting 
“Enquiries on the Zodiack of Den- 
derah,” and professes to prove that it 
does not reach higher than the year 
364 of the Christian era. 
M. Coquebert Montbret, reporter of 
thle “ Commission of Statistics,” after 
2K announcing 
