Compound Celluloses 



125 



rapidly dyes to an intense blue- black with a gain of weight 

 of from 20-50 p.ct. ; and the dyed fibre examined under 

 the microscope is of an intense transparent blue with all the 

 characteristics, that is to say, of a ' solid solution ' of the 

 colouring matter. 



The following is a brief account of the results of quantita- 

 tive observations. In our first series of observations we used 

 a solution of ferric chloride containing Fe 2 Cl 6 , equivalent to 

 0-0976 Fe 2 O 3 in 10 c.c., and an equivalent solution of ferri- 

 cyanide. Five equal portions, each weighing 2762 grms., of 

 jute fibre were treated with the mixture of the above solutions 

 in equal volumes, in the proportions and with the results given 

 in the subjoined table. 



It will be noticed that the Fe 2 O 3 fixed by the fibre is pro- 

 portional to the quantity taken, viz. approximately two-thirds 

 in each experiment ; but the corresponding increase in weight 

 of the fibre due to the blue cyanide fixed is somewhat variable. 

 The cyanide, in fact, is shown by analysis to vary in composi- 

 tion slightly in the ratio Fe : CN, more considerably no doubt 

 in its condition of hydration. The ash left on ignition of the 

 dyed fibre we find to contain no soluble basic constituents, 

 therefore no K 2 O appears to be fixed. 



Analysis of blue cyanide fixed by the fibre. A specimen 

 of fibre, dyed blue under the above conditions and weighted 



