190 Dr. Schunck on the Formation of Indigo-blue. 



hydrogen, adding a little acetate of lead to the filtered liquid, 

 filtering again, and precipitating completely with sugar of lead. 

 The precipitate, which was of a dirty-yellow colour, was filtered 

 off, and washed first with water and then with alcohol. 



I. 1'3345 grm., dried first .w vacuo and. then at 100° C, gave 

 0'9875 grm. carbonic acid and 0*2370 water. 



1"5825 grm. gave 0'4305 grm. chloride of platinum and am- 

 monium. 



08960 grm. gave 0'6630 grm. sulphate of lead. 



II. 1'3675 grm. of another preparation gave 1' 0485 grm. car- 

 bonic acid and 0'2470 water. 



1'5955 grm. gave 0*4325 grm. chloride of platinum and am- 

 monium. 



0'8895 grm. gave 06485 grm. sulphate of lead. 

 These numbers lead to the following composition :— 



828-8 100-00 100-00 100-00 



The following Table shows the composition of the substance, 

 after deducting the oxide of lead, as compared with that required 

 by theory :- 



This body may for the sake of distinction be called Oxindi' 

 casine. It is formed from oxindicanine by the latter taking up 

 water and losing 1 equivalent of indiglucine, since — 



leq.OxindicanineC40H23NO3n _ fC^^H'eNO^aieq.Oxindicasine. 

 3 eqs. Water H^ 0^ J ~ \ Ci^H'" 0'^ 1 eq. Indiglucine. 



C40H26N035 C40H26N035 



It is possible that there may exist a body which bears to oxin- 

 dicasine the same relation that indicanine does to oxindicanine. 

 This body would be Indicasine, and would differ from indicanine 

 by containing the element of 1 equivalent of indiglucine less. 

 The following analyses of a lead compound, which was obtained 

 as a pale yellow precipitate when a large quantity of alcohol was 



