Compound Celluloses 131 



the fixation of ferroso-ferric oxide more particularly to the 

 quinone or keto R. hexene groups of the non-cellulose ; the 

 resulting combinations being, however, rather of a ' molecular ' 

 character, they reunite to form the coloured lake or 'double salt ' 

 represented by the dyed fibre. Without reference, however, to 

 explanations of the mechanism of the reactions, which are for 

 the present more or less hypothetical, the following are the 

 facts to be emphasised in conclusion : 



(1) It is a reaction in which the lignocellulose manifests 

 itself as a homogeneous compound. 



(2) It is unique in the range of dyeing phenomena both in 

 regard to the formation of the colouring matter by definite 

 chemical reaction, and the very large proportion in which it is 

 fixed by the fibre-substance. 



This aspect of the reaction will be found discussed in the origi- 

 nal paper (loc. cit.\ and in a second communication on the sub- 

 ject (J. Soc. Chem. Ind., April 1894) in reply to criticisms by 

 C. O. Weber (ibid., March 1894). 



Compounds of Lignocellulose with Negative 

 Radicals. (a) Lignocellulose esters. (i) Benzoates. The 

 interaction of the lignocelluloses with the alkaline hydrates 

 and benzoyl chloride has been only superficially investigated. 

 Fixation of the benzoyl radical certainly takes place ; the fibre- 

 substance gains considerably in weight (36 p.ct), and analyses 

 of the products give results corresponding with the empirical 

 formula C 19 H 22 O 10 , which represents the fixation of i benzoyl 

 residue upon the empirical molecule Ci 2 H 18 O 9 of lignocellu- 

 lose. This proportion is about one half that of cellulose 

 (C 12 H 2 oO 10 ) under the same conditions. The result accords 

 with the observation of the partial yielding only of the fibre- 

 substance under the thiocarbonate reaction. From both we 

 may conclude that the ratio of alcoholic OH to the total oxygen 

 of the lignocellulose is low in comparison with cellulose. 



K2 



