286 
ON ALOINE. 
tions either of corrosive sublimate, nitrate of silver, or neutral 
acetate of lead. It also yields no precipitate with a dilute solu¬ 
tion of subacetate of lead ; but in a concentrated solution it 
throws down a deep yellow precipitate, which is pretty soluble 
in cold water, and is, therefore, difficult to wash. This preci¬ 
pitate is by no means very stable; and, when it is exposed even 
for a short time to the air, it becomes brown. 
When powdered aloine is thrown, in small quantities at a 
time, into cold fuming nitric acid, it dissolves without evolving 
any nitrous fumes, and forms a brownish-red solution. On 
adding a large quantity of sulphuric acid, a yellow precipitate 
falls, which, when it is washed with water to remove all adher¬ 
ing acid, and then dried, explodes when it is heated : it plainly, 
therefore, contains combined nitric acid. I could not, however, 
succeed in obtaining this compound in a crystalline state, as, 
when it was dissolved in spirits, it appeared to be decomposed. 
When aloine is digested for some time with strong nitric acid, 
much nitrous gas is evolved, and it is converted into chrysam- 
mic acid, but without the formation of any nitropicric acid, as is 
always the case when crude aloes is subjected to a similar 
treatment. A quantity of aloine was boiled with a mixture of 
chlorate of potash and muriatic acid. The acid solution was 
evaporated to dryness, and digested with strong spirits of wine. 
The greater portion of the spirits was removed by distillation; 
and the remainder, when left to spontaneous evaporation, 
yielded a syrup which could not be made to crystallize. Not 
a trace of chloranil was produced. 
When aloine is destructively distilled, it yields a volatile oil 
of a somewhat, aromatic odour, and also a good deal of resinous 
matter. When aloine is heated on platinum foil, it melts, and 
then catches fire, burning with a bright yellow flame, and emit¬ 
ting much smoke. It leaves a somewhat difficultly combustible 
charcoal, which, when strongly heated, entirely disappears, not 
a trace of ashes being left. 
A quantity of aloine dried in vacuo was analyzed with chro¬ 
mate of lead in the usual way. 
I. 0.2615 grm. aloine gave 0.5695 carbonic acid and 0.14 
water. 
II. 0.2415 grm. aloine gave 0.5250 carbonic acid and 0.126 
water. 
34 
C. 
Hydrated aloine. 
Calculated numbers. 
... 2550.0 
59.47 
Found numbers. 
I. 
59.39 
n. 
59.24 
19 
H. 
. 237.5 
5.54 
5.97 
5.79 
15 
O. 
. 1500.0 
35.09 
34.64 
34.97 
4287.5 
100.00 
100.00 
100.00 
