93 
action of alkalies is a question on which the author pro- 
nounces no decided opinion. 
For the purpose of obtaining the substances which he pro- 
posed to examine the author employed cotton yarn, which 
he preferred to unspun cotton for several reasons, the princi- 
pal being that yarn is comparatively free from mechanical 
impurities, such as fragments of seed-vessels, &c., while on 
the other hand, if proper care be taken, no impurity is 
added to those previously existing during the process of 
spinning. The yarn was boiled in an ordinary bleacher’s 
kier for several hours with a dilute solution of soda ash. 
The resulting dark brown liquor, after the yarn had been 
taken out, drained and slightly washed, was removed from 
the kier into appropriate vessels, and mixed with an excess 
of sulphuric acid, which produced a copious, light brown, 
flocculent precipitate, while the liquid became colourless. 
This precipitate was allowed to settle, the liquid was 
poured off, and after being washed with cold water to 
remove the sulphate of soda and excess of acid it was put 
on calico strainers and allowed to drain. A thick pulp was 
thus obtained, which when dried assumed the appearance 
of a brown, brittle, horn-like substance translucent at the 
edges. In one experiment 450 lbs. of yarn, made from 
East Indian cotton, of the variety called “ Dhollerah,” 
yielded 0 3 3 per cent, of the dried precipitate. In another 
experiment made with 500 lbs. of yarn, spun from Ameri- 
can cotton, of the kind called in commerce “middling 
Orleans,” 048 per cent, was obtained. The total loss sus- 
tained by yarn during the bleaching process amounts to 
about five per cent, of its weight. Only a small portion of 
the matter lost is therefore recovered by precipitation of 
the alkaline extract with acid. 
This precipitate formed more especially the subject of the 
author’s investigation. It was found to consist almost 
