COLOUR OF NANKIN COTTON. 369 



The other colouring-matter, on being analyzed, gave the 

 following results : — 



0*4450 grm., dried at ioo° C, gave 0*9374 grm. car- 

 bonic acid, and 0*2237 grm. water. 



0*7936 grm. gave 0*6288 grm. double chloride of plati- 

 num and ammonium. 



1*1854 grm. left, on being incinerated, 0*0054 grm. of 

 ash* =o*45 per cent. 



After correction for the ash, these numbers correspond 

 in 100 parts, to 



C 577° 



H 5-60 



N 4'99 



O 3171 



As regards their composition, these colouring-matters do 

 not, I think, differ more widely from the substances pre- 

 pared by the same process from ordinary cotton than is 

 frequently the case with bodies of the purity of which, in 

 consequence of their not assuming a crystalline form, one 

 can never be perfectly sure. The conclusion at which I 

 arrive, therefore, is that the colour of Nankin cotton is 

 due to the presence of bodies which are, if not identical 

 with, at least very similar to those which cause the much 

 fainter colour of the ordinary kinds. These experiments 

 show, too, that the substances accompanying the cellulose 

 (whether clothing the fibres or contained in their inte- 

 rior) are the same in this variety as in those previously 

 examined. 



* The ash was neutral to test-paper and of a reddish'colour ; it consisted 

 of alumina with traces of lime and oxide of iron. 



SER. III. VOL. V. 2 C 



