412 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
is soon converted into a mass of white crystals. These crystals have the properties 
and composition of crystallized g'rape sugar. 
0‘5015grm. of the crystals, dried in vacuo, gave 0’6830 carbonic acid and 0‘3380 
water. 
These numbers lead to the following composition : — 
Carbon 
Eqs. 
. . 12 
72 
Calculated. 
36-36 
Found. 
37-14 
Hydrogen 
. . 14 
14 
7-07 
7-48 
Oxygen . 
. . 14 
112 
56-57 
55-38 
198 
10000 
100-00 
It will now admit, I think, of little doubt, that the uncrystallizable sugar obtained 
from rubian in other processes of decomposition is merely modified grape sugar. 
The formation of chlororubiadine and sugar from chlororubian is a very simple pro- 
cess. The latter loses three equivalents of water and splits up into chlororubiadine 
and sugar, as will be evident from the following equation : — 
C,, H,; C10,,=C3, H, ClO,-l-C,3 H,, 0,,-h3H0. 
I have adopted the name of chlororubiadine, under the assumption that the true 
formula for rubiadine is C 32 H 13 O 9 . Nevertheless I have not succeeded in converting 
the latter into chlororubiadine by means of chlorine, nor in substituting the chlorine 
in chlororubiadine by hydrogen and thus forming rubiadine. If chlororubiadine be 
suspended in water to which an amalgam of potassium (1 part of potassium to 100 
mercury) is added, it dissolves with a dirty red colour without much hydrogen being 
evolved. The liquid gives a greenish-yellow flocculent precipitate on the addition of 
nitric acid. This precipitate contains no chlorine, but it does not contain any 
rubiadine, since it gives, after being dried and heated between two watch-glasses, 
none of the crystalline sublimate characteristic of rubiadine. The liquid filtered from 
this precipitate gives an abundant precipitate with nitrate of silver. 
Hydrosulphate of ammonia dissolves chlororubiadine, forming a red solution, which 
on standing becomes of a fine purple, and after some hours brownish-red. If nitric 
acid be added to the solution as soon as it has acquired a purple colour, an orange- 
coloured flocculent precipitate falls. This precipitate is free both from sulphur and 
chlorine, the chlorine of the chlororubiadine being found in the filtered liquid, but it 
contains no rubiadine. It is only partly soluble in boiling alcohol, but dissolves 
easily in boiling nitric acid, the solution depositing on standing some long dark 
yellow sword-shaped crystals. 
If crystallized rubiadine, obtained by the decomposition of rubihydran with acid, be 
dissolved in caustic alkali and reprecipitated with acid, and if the precipitated flocks 
after filtering and washing be suspended in water, and a current of chlorine gas be 
passed through the liquid, the flocks become somewhat paler in colour. If they be 
now collected on a filter and washed with water and then treated with cold alcohol. 
