178 THE CHINESE SUGAR CANE. 
cesses. First, treat the seeds with concentrated sulphuric 
acid ; allow them to remain in contact with it one or two 
days; then it is mixed in a large quantity of water; the 
whole is thrown upon a filter and washed until the 
liquor is no longer acid; the carbon which remains upon 
the filter, mixed with the coloring matter, is treated by 
warm alcohol, and gives a tint, which it is only neces- 
sary to distill, and add to it water, to obtain the purpur- 
holcine, in brilliant scales, tinged with a little fatty mat- 
ter. The liquid retains the yellow substances, and a 
little of the purpurholcine. 
‘Second: The seeds can be treated directly by alcohol 
and operated with, as above given for the alcoholic 
tincture; ether conduces to the same effect. 
“Third: We can furthermore employ a solution of pot- 
ash; it makes a brown magma, which is to be filtered; 
and in the hquor put with care some chlorohydric acid; 
brown flakes are precipitated, upon which will float a 
yellow liquid. These are to be separated, washed well, 
redissolved in alcohol, and the latter gives, by evapora- 
tion, the purpurholcine. 
“Uses: This coloring matter can be used for dyeing. 
By varying the dissolvents and the mordants, are ob- 
tained, upon cotton, woolen, and especially upon silk 
stuffs, beautiful tints, which vary as much as can be de- 
sired in the browns, the grays, the reds, thé oranges, 
and lilacs. Our conviction, in this respect, is based 
upon dyeing experiments, on a small scale. 
“The yellow matter, which we shall call xantholcine, is 
very soluble in water, either cold or warm. Soluble in 
acids, which cause it to become an orange yellow; the 
