Dr. Schunck on Rubian and its Products of Decomposition, 509 



state of putrefaction began to be emitted, then treated with 

 boiling alcohol until nothing more was dissolved, and dried. 



0*4630 grm., obtained in this manner and burnt with oxide of 

 copper and chlorate of potash, gave 0*7260 carbonic acid and 

 0-1760 water. 



0'.5270 grm. gave 0*2705 chloride of platinum and ammonium. 



0-2990 grm. gave on being incinerated 0*0720 carbonate of 

 lime, containing 0*04040 lime = 13*51 per cent. After treat- 

 ment with sulphuric acid, this yielded 0-0980 sulphate of lime, 

 containing 0*04042 lime = 13*52 per cent. 



In 100 parts it therefore consisted of — 



Carbon . . . . . . 45*65 



Hydrogen 4*22 



Nitrogen 3*22 



Oxygen 33*40 



Lime 13*51 



The only formula with which this composition agrees, and 

 which is at the same time in accordance with the preceding 

 formula?, is C^^R^^iW^O''^ + 3CaO, which requires in 100 parts- 

 Carbon 46*60 



Hydrogen 4*25 



Nitrogen 3*13 



Oxygen 33*48 



Lime .**.... 12*54 



From this formula it may be inferred, that during the further 

 progress of decomposition erythrozym loses ammonia in addition 

 to carbonic acid and water, for 



C'52H28iNi*028 + 4C02 -f. 4H0 + mE^=C'Hl^lS^O'^^. 



I shall conclude this part of my paper with a few remarks on 

 the vexata qucestio of the existence or non-existence of more than 

 one colouring matter in the madder root. Robiquet, the disco- 

 verer of alizarine, attributed the tinctorial power of madder partly 

 to that substance and partly to another, on which he bestowed 

 the name of purpurine. Gaultier de Claubry and Persoz were 

 of opinion that there are two colouring matters in madder. 

 Eunge has described three substances obtained by him from 

 madder, all of which he considers as colouring matters playing a 

 part in the process of madder dyeing. Schiel, Debus and Wolff 

 and Strecker all assume the existence of two distinct colouring 

 matters. Notwithstanding, however, the array of authority in 

 favour of this view, I have never been able to convince myself 

 that the entire tinctorial power of madder was not due to aliza- 



