ON ABSORPTION SPECTRA AND CHEMICAL CONSTITUTION. 



215 



The Absorption Spectra of Indophenols and Dyes derived from Triphenylmeihane. 



As much work has recently been published on the relationship between 

 the constitution of dyes and their absorption spectra, abstracts of the 

 more important of these memoirs are given, accompanied by remarks on 

 the conclusions drawn from previous examinations of triphenylmethane 

 derivatives. 



Relation entre la constitution chimiqioe des colorants du triphenylmethane 

 et les spectres d'absorjition de leurs solutions aqueuses. Note de M. P. 

 Lemoult.' 



The examination of the absorption spectra of a large number of 

 artificial colouring matters was made in the hope of finding some cha- 

 racteristic belonging to each of the principal groups which enter into their 

 constitution, but up to the present the study of such colours as are 

 derived from triphenylmethane has led to nothing more than a demon- 

 stration of some connection between the position of the luminous bands 

 of these spectra and the constitution of the products examined. All the 

 solutions were so made that a gramme-molecule of the dye was contained in 

 1,000 litres of water, the thickness of liquid being variable. The follow- 



ing were the substances investigated 



Phenyl blue, or phenylated 

 blue. 



Methyl green. 

 Hexamethylated violet. 

 Hexethylated violet. 

 Formyl violet. 

 Acid violet 10 B. 

 Benzyldiphenylamine violet, 

 Benzylated violet. 



• Comptes Rendus, vol. cxxxi. 1900, p. 839 



