Dr. Schunck on the Formation of Indigo-hhe. 191 



added to the liquid filtered from the lead compound of oxindica- 

 sine, seem to countenance the idea that such a body really exists. 



I, 0-9705 grm. of this precipitate, after being completely 

 washed with alcohol and then dried, at first in vacuo and then 

 at 100° C, gave 0-5740 grm. carbonic acid and 0-1645 water. 



1-2145 grm. gave 0-1210 grm. platinum. 

 0-6325 grm. gave 0-5420 grm. sulphate of lead. 



II. 1-3280 grm. of another preparation gave 0-7795 grm. 

 carbonic acid and 0*2145 water. 



1-5600 grm. gave 0-1435 grm. platinum. 

 0-8965 grm. gave 07715 grm. sulphate of lead. 

 Hence was deduced the following composition : — 



Eqs. Calculated. 

 Carbon . . 28 168 15-90 

 Hydrogen . 20 20 1-89 



Nitrogen . 1 14 1-32 



Oxygen . . 23 184 17-44 

 Oxideoflead 6 670-2 63-45 



1056-2 100-00 100-00 

 After deducting the oxide of lead, the composition in 100 

 parts, as compared with the theoretical composition, is as fol- 

 lows: — , ^ ,, 

 Eqs. Calculated. I. J^- 



Carbon . . 28 168 43-52 43-65 43-63 



Hydrogen . 20 20 5-18 5-08 4-88 



Nitrogen . 1 14 3-62 3-81 8'54 



Oxygfn . 23 184 JT^eS ^7:46 47-96 



386 100-00 100-00 10000 



Now if the formula of this substance be doubled, and the 

 formula of oxindicasine be deducted, the remainder will be the 

 formula C2«IP''N0^^3, since 



C56 H40 N2 O''^ = C28 H»^ N023 + C28 H'^^ N023. 



The body represented by the last formula and 1 equivalent of 

 indiglucinc contain together the elements of indicanine and 

 water, for 



C29 H24 N023 + C>2 RIO O'^ssC'"' H23 N02'» + IIHO. 



It has therefore the composition which theory would assign 

 to indicasinc, and the substance represented by the formula 

 C28 1^20 jyjo^'^ is probably a mixture in equal proportions of indi- 

 casinc and oxindicasine. By decomposition of the lead compound 

 with sulphuretted hydrogen and evaporation of the filtered liquid, 

 this substance ia obtained in the form of a brown syx-up, which 



