1864. | Chemistry. 457 
position of the substance of the plant. They also maintain that the 
decomposition of carbonic acid by the green parts of aquatic plants, 
does not give rise to the formation of carbonic oxide as has been stated 
by Boussingault. 
M. Cloez also says that the coloured parts of plants do not decom- 
pose carbonic acid so as to give off oxygen. If in some cases coloured. 
leaves have been stated to do so, this depends he thinks on some green 
being present in them. He shows that in the coloured leaves of Amaran- 
thus tricolor, the green portions only decomposed carbonic acid and 
gave off oxygen, while the yellow and red portions did not give off 
a single bubble of gas. These conclusions are contrary to the opinion 
of M. Theodore de Saussure. 
IV. CHEMISTRY. 
(Including the Proceedings of the Chemical Society.) 
To chronicle with any degree of completeness the progress of a 
science which daily makes such advances as Chemistry, would require 
every quarter more than the whole of our space. We can only, therefore, 
continue to select those examples which seem to possess the greatest 
interest for general readers, and leave the special student of the science 
to seek ihe details in journals devoted entirely to the subject. 
In general inorganic chemistry one or two interesting discoveries 
have been made. ‘The first we shall mention is that of M. Le- 
moine, who has found that the red modification of phosphorus 
combines with sulphur in but one proportion.* 'The new sulphide 
has the formula P,§,. It is a remarkably stable compound, having a 
distinct crystalline form. It is remarkable also that this compound 
is always formed, whatever the proportion of the constituents may 
be employed in the experiment. This sesquisulphide of phosphorus, 
as we must call it, is soluble in sulphide of carbon, which atiords a 
ready means of separating it from the uncombined red phosphorus. 
The fact that one element in an allotropic modification combines with 
another element in different proportions to what it does in the ordi- 
nary state, may not be without some significance. 
Proceeding with the inorganic elements, we must notice the dis- 
covery of the metal cesium in an unexpected place. It is now some 
years since Plattner analysed Pollux, a scarce mineral found in the 
island of Elba. He pronounced it to be a compound of silica, alumina, 
soda, and potash ; but in his analyses he always had an inexplicable 
loss. Recently, M. Pisanit has analysed the same mineral, and has 
discovered that it contains 34 per cent. of cesium; and calculating 
for this metal, the amount set down by Plattner as potassium, the per- 
centage sum of the constituents is exactly made up. 
* «Comptes Rendus,’ May 16. 
+ ‘Comptes Rendus,’ May 18. 
