572 
sition; and he explains the action of air ~ 
and moisture from their destroying the 
cohesion of the mineral. 
M. Leligvre, has described a mineral 
which was also supposed to be spathic 
iron, and which is found to contain more 
than one half of oxide of manganese, com- 
bined with nearly a third of carbonic 
acid, and only eight centimes of iron, 
and two centimes and a half of lime. 
It may, therefore, be considered as a new 
species of carbonate of manganese. 
The same mineralogist,’ the reporter 
proceeds to inform us, has described a 
stone which he discovered in the Isle of 
“Elba. _ It contains more than one-half 
of its weight of oxide of iron, and a little 
oxide of mangafese. The remainder is 
composed of silica and lime. Its crys- 
talline nucleus is a prism with a rhom- 
boidal base, of an opague and black co- 
Jour. Its hardness 1s but little inferior 
to that of feldspath, and its specific g ora 
vity four times greater than that of dis- 
tilled water. M. Lelitvre has bestowed 
on it the appellation of yenite.  ~ 
M. Bavaillon, correspondent of the 
historical class, having discovered in dig- 
zing the ground near the ancient city of 
Neris, hard by Monthicon, some antique 
pewter vases, M. Mongez, member of 
the same class, was anxious to ascertain 
their degree of purity. From an analysis, 
undertaken at his entreaty by M. An- 
frye, mspector-general of the mint, they 
’ were found to contain three-tenths and a 
half of lead. It 1s well known from 
the analysis of M. Proust, that such a 
portion of alloy is attended with no 
danger. 
Tn ovr last year’s report, we noticed 
an important applica .fion of chemistry to 
the arts, which consists in rendering com- 
mon equal to Roman alum for the pur- 
pose of dyeing, by freeing it from the small 
portion ot iron which it contains. 
Among the different means cup oer 
for this purpose, we may mention that 
adopted by M. Seguin, founded on the 
different degrees of solubility of pure 
alum, and of that impregnated with iron. 
Ele dissolves sixteen parts of common 
alurn in twenty-four parts of water, leaves 
them to crystallize, and by this means 
obtains fourteen parts of alum, equal in 
purity to that of Roman alum, and two 
parts nearly equal to that of Liege. 
We may apply this process from the 
beginning, and thus obtain an alum 
about one-third more valuable, 
The same chemist continues his labours 
on the analysis of vegetable juices. 
4 
Proceedings of Learned Societies. 
‘at ditferent periods. 
Into the recipient, 
[Jan. i, : 
In the last half-yearly report, he has 
treated of those which contain no tannin, 
they have all more or less of the albumi- 
nous and bitter principle. In proportion 
to the abundance of the albumen, their 
odour is stronger, and the more readily 
does the juice become subjected to pu- 
trefaction. Mushrooms, cruciform and 
solanaceous plants, are of this kind. M. 
Seguin has favoured us with some obser~ 
vations respecting the proportions of 
these two principles, in the twenty-two 
natural families of plants, and pointed 
out to us in several of the differences of 
these proportions in the different parts 
of the vegetable, and in the same plant 
All these juices, 
treated with the sulphuric acid, or the 
muriate of tin, acquire the odour either 
of roasted pears or apples, or of some 
fermented liquor, as cyder and beer. 
What renders these sort of researches 
so difficult, arises from the various re= 
actions and combinations which occur 
between different elementary substances, 
which are not, however, very numerous 
in themselves. 
Of this we have had new proofs in the 
memoir of M. Thenard, professor in the 
French College, respecting nitric ether. 
It is well known, that ethers are odo- 
rous and combustible liquors, which are 
obtained by treating alcohol with acids, 
That, with which we are best acquainted, 
is sulphuric ether. 
From the researches of Messrs. Four- 
croy and Vauquelin, we now know the 
progress of its formation, and all the com- 
bimations which take place with it, The 
theory of nitric ether was less perfect. 
What they sold for such in the shops 
was not even a true ether. Nitric ether 
is composed, as is well known, of azot 
and oxygen; alcohol, of carbon, hydro- 
gen, aud oxygen. "These two liquors 
therefore contain four elementary sub- 
stances, and form by their union ten 
combinations susceptible of separation ; 
pamely, much water, much of the gase- 
ous oxide of azot, much ether, a small 
portion of gazecus oxidule of azot, ni- 
trous gaz, of carbonic acid gaz, of acetic 
acid, and of a matter which 1s. readily 
carbonized. A portion of these substan- 
ces remains in the first vessel where the 
mixture is made; another portion passes 
by distiliation, and 
assumes in it a liquid form, while the 
third remains in a gazeous state. 
This last portion - is nearly wholly cam- 
posed of ether, and in order to obtain it 
separately, iv is necessary to pass the gaz, 
through 
