FORMATION OF INDIGO-BLUB. 2 1 1 



Though this is the only way in which I am able to explain 

 these discrepancies, still I failed in all my efforts to separate 

 any specimen of the substance having an intermediate com- 

 position into two distinct constituents, as every such specimen 

 behaved towards all reagents as if it were one single sub- 

 stance. By treating however a specimen of this kind with 

 a boiling solution of caustic soda for a length of time, the 

 percentage of carbon was increased by about 2.5, showing 

 that the body whose formula is C 24 H 10 N 9 has a tendency 

 to lose carbonic acid and be converted into the one whose 

 composition is expressed by the formula C M H 10 NO«. The 

 substance used in this experiment was that employed for the 

 analysis No. III. It was dissolved in caustic soda, the solu- 

 tion was boiled for some time and then mixed with an excess 

 of muriatic acid. The precipitate produced by the acid was 

 dissolved in alcohol and ammonia, and the solution having 

 been mixed with an excess of acid deposited a brown powder, 

 which after being collected on a filter, washed and dried was 

 analysed, when it was found to contain 63.22 per cent, of 

 carbon. 



Indiretine. 



This body, the most striking properties of which have been 

 already mentioned in the first part of this paper, appears on 

 evaporation of its alcoholic solution in the form of a dark 

 brown, shining resin, which is transparent only in very thin 

 layers. It resembles indifulvine in appearance but is dis- 

 tinguished from the latter by its being easily soluble in all 

 alkaline liquids. When heated on platinum foil it melts, 

 swells up very much and burns with a yellow smoky flame, 

 leaving some charcoal which slowly burns away. When 

 heated in a tube it swells up and gives strong smelling fumes 

 together with an oily sublimate, resembling that obtained 

 from indifulvine, which when cool becomes half solid. Con- 



