PRODUCTS DEBIVED FROM INDIGO-BLUE. "T^ 



of the substance led to different results, as the following 

 details will show : — 



I. 0*38 10 grm. gave 1*0600 grm. carbonic acid and 

 0*2385 grm. water. 



0*7280 grm. gave 0*5000 grm. chloride of platinum and 

 ammonium. 



II. 0*4015 grm. gave i*i200 grm. carbonic acid and 

 0*2500 grm. water. 



0*6235 grm. gave 0*4265 grm. chloride of platinum and 

 ammonium. 



These numbers lead to the fprmula Cgo H44 N^ 0,o, which 

 requires 



Experiment. 

 Calculation. I. II. 



Cgo 480 75*94 75*87 76-07 



H44 44 696 6-95 691 



^2 a8 • 4*43 4'3i 4*29 



Oio 80 iz-67 12-87 1^*73 



623 lOO'OO lOO'OO lOO'OO 



Though this formula differs widely from the first, it 

 presupposes a similar mode of formation for the substance, 

 the only difference consisting in the relative quantities 

 of the elements uniting to produce it, as will be seen from 

 the following equation : — 



Indigo-blue. Alcohol. Acetic acid. 



C30 H^^N, 0,0+28 H0=2(C,e H, NOJ+9(C,HeO,)-f 2(0^ H, 0,)+4C0,. 



It appears, therefore, that in both cases its formation was 

 due to the union of indigo-blue with alcohol, acetic acid, 

 and carbonic acid, accompanied by the loss of a certain 

 proportion of water. The alcohol and acetic acid are in- 

 gredients employed in the process ; but it is not easy to see 

 whence the carbonic acid is derived. I think, however, it 

 may originate in the formation of anthranilic acid. This 

 acid, as is well known, is produced by the action of caustic 

 alkalies on indigo-blue, which, taking up water and oxygen. 



