A, H. Chester—Crystallization of Variscite. 207 
The results indicate a mixture of C,,H,,N, and 2(C,H, ,S). 
The oil has the odor of thiovaleral, and decomposes when dis- 
tilled. Hydrochloric acid added to the concentrated etherial 
solution of it produces a white curdy mass which was not ob- 
tained free from adhering oi]. This last product is soluble in 
alcohol, ether, and with the separation of an oil in hot water. 
Platinic chloride produces at once in the alcoholic solution a 
small light yellow precipitate and in a few minutes a dark 
brownish red curdy precipitate which yields to water, platin- 
chloride of ammonium. ‘The red precipitate after washing 
with water and alcohol, reacts for platinum, sulphur and a hydro- 
carbon. Lack of material prevented further investigation of the 
oe a from amylidenamine silver nitrate by the action of 
ydrogen sulphide. 
New Haven, January 10, 1878. 
ArT. XXXI.—WNote on the Crystallization of Variscite ; by 
ALBERT H. CHESTER. 
A MicroscoPic examination of certain small crystals of the 
mineral variscite from Arkansas reveals the following facts with 
reference to its method of occurrence and crystallization. 
The crystals are rarely distinct, but are usually found in 
complicated groups, sometimes forming clusters of a sheaf form. 
Very rarely single prismatic crystals are found, sufficiently dis- 
1. 2. tinct to admit of measurement. 
Fig. 1 AoE the most common 
ee form, belonging to the orthorhom- 
bic system, and showing faces of 
J, %, it and O. In this crystal 
I,f=114° 6’. In general but 
one termination is seen, but crys- 
tals showing both ends aré some- 
times found lying on the quartz 
matrix, the bases being similar 
to each other. The face 7 is 
very small and therefore easily 
overlooked, and 7% is about the same size as J, so that these 
crystals may readily be mistaken for hexagonal prisms. Crystals 
showing a simple termination like that in fig. 1 are seldom seen. 
More frequently the basal plane is like fig. 2, or still more 
complicated. ‘These planes are often covered with a thin 
Opaque white coating, probably of quartz. : 
striking peculiarity of this mineral is its high lustre, like 
that of beryl, which it much resembles when viewed under a 
low power.” The crystal figured above is 0°3 mm. in diameter, 
and is about the average size of those examined. 
Hamilton College Laboratory, January 19th, 1878. 
