92 
says that the woody fibre constituting the tissues of cotton, 
hemp, linen, &c., is not pure; it contains 1st, a certain 
quantity of colouring matter, which is more or less shielded 
from the action of decolorising agents by the bodies which 
accompany it, naturally or accidentally; 2ndly, a peculiar 
resin natural to the fibre, insoluble in water and soluble 
with difficulty in alkalies, which plays the part of a reserve 
and protects the colouring matters inherent in the fibre from 
the action of the agents which ought to destroy and remove 
them ; 3rdly, a certain quantity of fatty matter, of which a 
very small portion is peculiar to the fibre, the greatest part 
being derived from the operations of spinning and weaving ; 
4thly, a neutral substance, either flour, starch, or glue, which 
has been introduced by the weaver in sizing his warp ; 5thly, 
inorganic saline matters, some of which belong to the fibre, 
while the others are derived from the water and the matters 
employed in the dressing of the warp. In the excellent article 
on Bleaching in the new edition of Ure’s Dictionary of A rts 
there is a full account of these and other impurities of cotton 
fabrics, comprising all that was known at the time when the 
author commenced his examination. 
The object which the author had in view in undertaking 
his investigation was to endeavour to throw a little more 
light on the nature of those substances which are contained 
in or attached to the framework of cellulose, of which 
cotton fibre mainly consists, and which are together with 
the latter produced by the plant. All foreign and extra- 
neous matter introduced during the process of manufacture 
was therefore left entirely out of consideration. The 
author has further confined his attention to those consti- 
tuents of the fibre which are insoluble in water but soluble 
in alkaline lye, and are afterwards precipitated by acid from 
the alkaline solution. Whether cotton contains naturally 
any substance soluble in water, qr which being originally 
insoluble is rendered soluble therein by the prolonged 
