512 Dr. Schunck on Rubian and its Products of Decomposition » 



which no trace of anything crystalline was discernible. Its 

 analysis gave the following results : — 



0*4820 grm. gave 1-1240 carbonic acid and 0*1800 water. 

 0*8060 grm. left on being incinerated 0*0310 aluraina=3*84 

 per ceijt. 



After making the proper correction for the alumina, the 

 quantity of which, in relation to that of the other constituents, 

 seems to be indefinite, these numbers correspond in 100 parts 

 to- 

 Carbon 66*13 



Hydrogen 4*31 



Oxygen 29*56 



This composition does not differ vei-y widely from that given 

 for oxylizaric acid by Debus. 



Now the formula C^ W O^^ = C^^ H^ O^ + SCi^ H^ 0-^ requires 

 in 100 parts — 



Carbon 66*14 



Hydrogen 3*93 



Oxygen 29*93 



A quantity of material similar to the last, obtained on a dif- 

 ferent occasion, was treated in the same way with boiling alum 

 liquor, and the deposit formed on the liquor cooling was sub- 

 mitted to analysis. It had a much lighter colour than the 

 preceding, and when dissolved in alcohol, the latter left on 

 evaporation crystals, apparently of alizarine, mingled with red 

 crystalline masses resembling impure alizarine. 



0*4000 grm. gave 0*9870 carbonic acid and 0*1390 water. 



0*3840 grm. left on being incinerated 0*0060 alumina=l*56 

 per cent. 



After making the necessary correction for the alumina, these 

 numbers correspond in 100 parts to — 



Carbon 68*36 



Hydrogen 3*92 



Oxygen 27*72 



The formula C"^ H^^ O^-^^ZC'" H^ 0^ -F C^^ H^ 0^ requires in 

 100 parts- 

 Carbon 68*29 



Hydrogen . . . * . 4*06 



Oxygen 27*65 



These two specimens therefore of a substance prepared in the 

 same way, both of which would, according to the definition of 

 Wolff and Strecker, pass for purpurine, possessed a composition, 

 which in the one case coi-responded to a mixture of 1 equiv. of 

 alizarine and 3 equivs. of verantine, in the other case to a mix- 

 ture of 3 equivs. of alizarine and 1 equiv. of verantine. A still 



