MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 103 
0*4630 grm.j 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 treatment 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 formulae, is C52 Ojg+SCaO, 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 decom- 
position erythrozym loses ammonia in addition to carbonic acid and water, for 
C52 H28J Nij 028+4C02-|-4H0-1--|-NH3=C56 H 34 N 2 O 40 . 
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 discoverer 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. Runge 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, 1 have never been able to convince myself that the entire 
tinctorial power of madder was not due to alizarine alone, and that consequently all 
substances derived from madder, if endowed with any such power, owe it to their 
containing alizarine ; and after having isolated and examined the primitive substance, 
from which all the bodies in madder endowed with a red or yellow colour, or capable 
of producing these colours, are derived, and after having exposed this substance to 
p 2 
