454 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
In 100 parts it therefore contains — 
I. 
II. 
III. 
IV. 
V. 
VI. 
Carbon . . 
. . 67*87 
68*19 
68*70 
68*24 
68*66 
68*06 
Hydrogen . 
. . 5*04 
5*07 
5-38 
5-30 
5*20 
5*03 
Oxygen 
. . 27*09 
2674 
25*92 
26*46 
26*14 
26*91 
I endeavoured in vain to determine the atomic weight of this substance. Neither 
the lead nor the baryta compound gave results which harmonized either with one 
another or with the analyses of the substance itself. There is however only one for- 
mula which is in accordance with the analyses, and at the same time satisfactorily 
explains its formation. This formula is C 14 H 6 O 4 , which requires in 100 parts — 
Carbon 68'85 
Hydrogen 4*91 
Oxygen 26 24 
It may be remarked that this is also the composition of benzoic acid ; and even if 
the formula of rubiretine should not be exactly that given above, but perhaps the 
double or triple of it, it still remains remarkable that two such very ditferent sub- 
stances should have the same percentary composition. 
The formation of rubiretine from rubian can only be explained in connection with 
that of verantine. If 2 equivs. of verantine, 2 equivs. of rubiretine and 12 equivs. of 
water be added together, the sum will be equal to 1 equiv. of rubian, as follows ; — 
2 equivs. of Verantine =C23 Ojo 
2 equivs. of Rubiretine=C 28 H ,2 O g 
12 equivs. of Water = H ,2 0^2 
1 equiv. of Rubian =€58 H 34 O 30 ' 
If this be the correct representation, it follows that verantine and rubiretine stand 
in an intimate relation to one another, that the formation of one always indicates 
that of the other. In confirmation of this view, I may state that I have never seen 
the formation of one of these substances taking place without it being possible to 
detect the presence of the other. 
Ruhianine . — This substance, as I mentioned before, has not hitherto been observed 
among the bodies derived from madder. It greatly resembles rubiacine in its appear- 
ance and many of its properties ; it may however easily be distinguished by several 
characteristies, and above all by its composition. It is obtained from a solution in 
boiling alcohol in the form of bright lemon-yellow, silky needles, which, when dry, 
form an interwoven mass. It is soluble in boiling water, more so in fact than any of 
the products of decomposition hitherto mentioned. It crystallizes out again on the 
solution cooling in yellow silky needles. It is less soluble in alcohol than the pre- 
ceding substances. Its colour is lighter than that of rubiacine. When heated on pla- 
tinum-foil it melts to a brown liquid, then burns, leaving a carbonaceous residue. 
