324 MR C. G. WILLIAMS ON THE VOLATILE BASES 
Bichromate of Lepidine.—This extremely beautiful salt is easily obtained by 
adding an excess of a rather dilute solution of chromic acid to lepidine. For the 
first few seconds the chromate, on touching with a glass-rod, appears resinous, 
but the instant it is stirred the salt becomes gritty and crystalline. On filtering 
off the crystalline powder obtained in this manner, and dissolving it in hot water, 
the salt crystallizes out on cooling, in needles nearly an inch long, extremely 
brilliant, and of a rich golden yellow. The mother liquors, on evaporation, yield 
a fresh crop. It does not appear to be at all decomposed by moderate boiling 
with excess of dilute chromic acid. It decomposes at no very elevated tempera- 
ture, and if suddenly heated to 212° when slightly damp, it becomes converted into 
a mixture of green oxide of chromium and charcoal. On one occasion, this took 
place with a very curious phenomenon. About four grains in powder having been 
placed on a water-glass, on the upper shelf of the water-bath, it was not observed 
for about one hour, during which time it had become converted into a mass of 
flattened rods, reaching to the top of the water-bath, a distance of about 14 inches, 
and had turned down again on all sides, in a manner which gave the whole much 
the appearance of the capital of a Corinthian column. In general, however, it 
may be dried at 212° with perfect safety ; if retained more than an hour or two in 
the bath it begins to turn slightly brown, but experiences no further change during 
five hours’ exposure. On ignition, the salt behaves like the bichromate of ammonia 
and the chromate of strychnine, inasmuch as it leaves pure green oxide of chro- 
mium. This fact enables the constitution of the salt to be determined with accu- 
racy. The following experiments were made upon three different specimens. 
4-105 grains of bichromate lepidine, dried at 212°, gave 
uy { 1:260  ... green oxide of chromium. 
qr, { &290 grains of bichromate lepidine, dried at 212° until slightly brown, gave 
: { 1:940 ... green oxide of chromium. 
II 6-850 grains of bichromate lepidine, dried at 212° for five hours, gave 
; { 2120  ... green oxide of chromium. 
7-315 grains of bichromate lepidine gave 
IV.< 12-620  ... carbonic acid, and 
2°560 ... water. 
Experiment, Calculation. 
SS SSS ——_—_—_—_— 
I. Wy) III, DV 
Carbon, : Ae ae we. 47°05 47°36 Coy 120-0 
Hydrogen, . Seb ont id 3°89 3°95 Hi, 10-0 
Nitrogen, . aoe coe 358 430 5°52 N 14:0 
Chromium, . Piel] P22 Mabie: 21:07 Cr, 53-4 
Oxygen, one odb Ato 22:10 0, 56:0 
100-00 253-4 
Consequently the formula, is 
C,, H, N + 2Cr 0, + HO. 
The salt analysed agrees therefore with the bichromate of ammonia in only con- 
taining one atom of water. 
