OF INDIGO-BLUE. 207 



ie consisting of indihumine was analysed, when the 

 following numbers were obtained : — 



0.3065 grm. dried at 100°C. gave 0.7065 grm. carbonic 

 acid and 0.1300 water. 



0.3285 grm. gave 0.3765 grm. chloride of platinum and 

 ammonium. 



From these numbers it may be inferred that the compo- 

 sition is as follows : — 



Eqg. Calculated. Found. 



Carbon 20 J20 62.82 62.86 



Hydrogen 9 9 4.71 4.71 



Nitrogen 1 14 7.33 7.19 



Oxygen 6 48 25.14 25.24 



191 100.00 100.00 



Indifuscine. 



This body so much resembles the preceding in its outward 

 appearance and most of its properties, that the two might 

 easily be confounded. Indifuscine is always obtained in the 

 shape of a dark brown powder, exhibiting sometimes a red- 

 dish tinge. It is insoluble in boiling water and only slightly 

 soluble in boiling alcohol, the solution being light brown and 

 depositing a great part of the substance on cooling in brown 

 flocks. It is easily soluble in a mixture of alcohol and am- 

 monia. The solution is dark brown and opaque, and when 

 it is mixed with an excess of muriatic or acetic acid the 

 greatest part of the indifuscine is deposited in the form of 

 a brown powder, while the supernatant liquid retains a brown 

 colour, which is rather darker than that of the solution of 

 the substance itself in boiling alcohol. It is also soluble in 

 watery solutions of caustic and carbonated alkalies, forming 

 brown solutions, from which it is precipitated again by adds 

 in brown flocks. The amnion iacal solution gives brown pre- 

 cipitates with salts of baryta, lime, magnesia, alumina, iron, 

 zinc, copper, lead, mercury, and silver, the whole of the in- 



