318 
MISCELLANY. 
Roman chamomile, which greatly resembles valerianic acid, if it be 
not identical with it. He however only obtained 2 h drms. from 24 
lbs. of dry flowers, while the same quantity yielded from 4 to 6 ozs. 
of the most beautiful essential oil, therefore far more than is usually 
stated. From flowers which had been kept for a long time much less 
essential oil is obtained than from fresh. The author, on distilling the 
flowers of Anthemis nobilis, obtained 1" 17-1-10 per cent oil and 0'81 
per cent, of a peculiar volatile acid, while Wyss obtained only traces 
of it in his analysis. — Ibid, from Archiv. der Pharm. 
On the Artificial Production of Diaphanous Quartz. By M. Ebelmen. 
— When either of the two silicic aethers which I have recently de- 
scribed is exposed to the continued action of a moist atmosphere, the 
liquid finally solidifies to a transparent mass. This product, very de- 
licate and fragile in the first days after its solidification, contracts more 
and more under the influence of the moist air still remaining diapha- 
nous. Two or three months are requisite in operating on 5 or 6 grms. 
of aether, for the substance to cease to lose in weight and for its mole- 
cular movement to terminate. The substance prepared as above is 
hard, faintly scratches glass, and possesses great cohesion ; its lustre, 
its fracture and transparency are perfectly comparable to the most 
beautiful rock crystal. Its density is 177. It is a hydrate, which 
contains twice as much oxygen in the silica as in the water, the formu- 
la of which is consequently (SiO) 2 HO. 
It is essential, in order that the product may not become fissured 
during the contraction it experiences before attaining the definite 
formula (SiO) 2 HO, not to allow the moist air to enter except by an 
aperture of very small diameter. During the whole of the experi- 
ment the flask containing the silicic aether exhales an alcoholic odour, 
which persists a long time after the solidification, proving that only a 
portion of the organic matter had separated from the silica when the 
solidification took place. The contraction proceeds the more slowly 
the less easily the moist air is renewed in the apparatus, and this 
slowness appears indispensable to the success of the operation. 
From the properties of the hydrate of silica, we may be allowed to 
hope that it may be turned to advantage in the construction of optical 
instruments. It is my intention to make some experiments in this 
direction. — Ibid, from Comp. Rcndus. 
On the Artificial Production of Hydrophane. By M. Ebelmen. — By 
slightly modifying the process for the preparation of hydrate of silica, 
