FROM THE POLYGONUM FAGOPYRUM. 127 
yellow precipitate, the supernatant liquid remaining 
muddy for a long time. 
Printed calico, when immersed in the warm watery 
solution of this colouring matter, becomes fully dyed, the 
alumina mordant acquiring a dark yellow colour, the tin 
mordant a light yellow, and the iron mordant various 
shades of yellowish-brown according to the strength of 
the mordant employed. Silk and wool do not acquire any 
colour in the boiling watery solution, unless they have 
been previously prepared with some mordant. 
The substance contains no nitrogen, for on being treated 
with boiling caustic soda lye, or heated in a tube with 
soda-lime, it evolves no ammonia. Its composition was 
determined by the following analyses : — 
I. 0:4145 grm. of the substance, crystallised from alco- 
hol, dried at 100°C. and burnt with chromate of lead, gave 
0.7550 grm. carbonic acid and 0:2200 water. 
II. 0:4085 grm. crystallised from water, gave 0°7450 
grm. carbonic acid and 0°2130 water. 
III. 0:4205 grm. of another preparation gave 0°7715 
grm. carbonic acid and 0°2255 water. 
IV. 0:4170 grm. gave 0.7640 grm. carbonic acid and 
0°2225 water. 
These numbers correspond in 100 parts to 
E II. STE. IV. 
Carbon........ 49°67 49°73 50:03 49°96 
Hydrogen..... 5°89 5:79 5°95 5°92 
4 ee 44044. 44:48 44-02 44°12 
100:00 = 100:00 100:00 100-00 
The lead compound was prepared by adding to the 
alcoholic solution an alcoholic solution of acetate of lead. 
The dark yellow precipitate was collected on a filter, 
