28 
on the addition of acid, and I therefore examined them 
with more care than the other constituents of the 
precipitate. These colouring matters I found to be at 
least two in number. One of them is easily soluble in 
alcohol and is obtained on evaporating the solution as 
a dark brown, shining, transparent resin. The other 
is almost insoluble in cold alcohol, but dissolves in boiling 
alcohol, and is deposited on the solution cooling in the form 
of a light brown powder. Their properties are in genera] 
the same as those of the analagous colouring matters from 
ordinary cotton. They contain, like these, C, H, N, and O, 
but in somewhat different relative proportions. Their com- 
position in 100 parts I found to be as follows : 
A. B. 
Colouring matter 
soluble in 
cold alcohol. 
Colouring matter 
insoluble in 
cold alcohol. 
C 58-22 
H 5-42 
N 3 73 
0 32-63 
C ..... 57-70 
H 5-60 
N 4-99 
0 3T71 
The composition of the analogous colouring matters from 
American cotton according to previous determinations was 
as follows : — 
A. 
B. 
c ... 
... 58-42 
C ... 
... 58-36 
H ... 
H ... 
... 5-71 
N ... 
... 5-26 
N ... 
... 7-60 
0 ... 
... 30-47 
0 ... 
... 28-33 
The difference in composition, in the first case at least, is 
not greater than may be expected with substances of the 
purity of which, in consequence of their not occurring in a 
crystallized state, one can never be perfectly sure. On the 
whole, I think these experiments justify the conclusion at 
which I have arrived, viz., that the colour of Nankin cotton 
is due to the presence of bodies which are very similar to, 
if not identical with, those which cause the much fainter 
