CONSTITUENTS OF COTTON-FIBRE. 117 



the colouring-matter B, pounded it very fine, added a little 

 concentrated sulphuric acid and then absolute alcohol, after 

 which the whole was well stirred in a mortar and left to 

 stand for some time. The liquid, which had a brown 

 colour, was filtered and mixed with water, which gave a 

 brown precipitate. This was filtered ofi", washed with 

 water, and dissolved in boiling alcohol. The solution 

 left, on evaporation, a brown resinous residue, which was 

 almost insoluble in cold alcohol, and contained, therefore, 

 none of the colouring-matter A. 



In determining the composition of this substance the 

 following results were obtained : 



I. 0*4030 grm. prepared from East-Indian cotton and 

 dried at ioo° C. gave 0*8370 grm. carbonic acid and 0*2245 

 grm. water. 



0*6920 grm. gave 1*0240 grm. chloride of platinum and 

 ammonium. 



II. 0*4000 grm of the same specimen gave 0*8345 grm. 

 carbonic acid and 0*2230 grm. water. 



0*6970 grm. gave 1*0535 grm. chloride of platinum and 

 ammonium. 



1*2005 gi*ni. left on being incinerated 0*0135 grm. of 

 ash= 1*12 per cent. 



III. 0*4005 grm. of another specimen from East-Indian 

 cotton gave 0*8355 grm. carbonic acid and 0*2265 grm. 

 water. 



0*7015 grm. gave 1*0575 grm. chloride of platinum and 

 ammonium. 



0*5870 grm. left 0*0045 grm. of ash = o*76 per cent. 



IV. 0*4015 grm. from American cotton gave 0*8505 

 grm. carbonic acid and 0*2060 grm. water. 



0*7045 grm. gave 0*8615 grm. chloride of platinum and 

 ammonium. 



V. 0*4230 grm. of the same gave 0*8930 grm. carbonic 

 acid and 0*2130 grm. water. 



