80 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
In 100 parts it contained therefore — 
Carbon 40‘97 
Hydrogen ^‘72 
Oxygen 53'31 
On redissolving the remainder in water, it gave a brown solution, but on adding to 
the solution hydrated oxide of lead, the brown portion was removed, while the solu- 
tion became almost colourless, and on evaporation over sulphuric acid left a yellow 
syrup, the composition of which again corresponded with the formula C 12 H 12 O 12 , as 
will be seen by the following analysis : — 
0-3710 grni. gave 0-5535 carbonic acid and 0-2135 water. 
In 100 parts : — 
Carbon 40-68 
Hydrogen 6-39 
Oxygen 52-93 
Huhiafine . — In my former papers on madder I have described a substance which I 
called rubiacine, and which I prepared partly from madder itself, and partly by the 
reduction of rubiacic acid with sulphuretted hydrogen. Now rubiafine cannot be 
distinguished by any of its properties from rubiacine. It crystallizes from its alco- 
holic solution in yellow glittering plates and needles, which are sometimes arranged 
in star-shaped or fan-shaped masses. By carefully heating it, it may be volatilized 
without leaving much residue, forming a yellow sublimate of small shining needles. 
It is but slightly soluble in boiling water. It is not decomposed by boiling nitric 
acid or by concentrated sulphuric acid, but merely dissolved by them. It dissolves 
in caustic alkalies with a reddish-purple, and in carbonated alkalies with a red colour. 
Its alcoholic solution gives with sugar of lead a fine crimson precipitate, with ace- 
tate of copper an orange-coloured precipitate. It dissolves in a solution of pernitrate 
of iron with a dark brownish-purple colour. The solution, after being boiled for 
some time, gives, on the addition of muriatic acid, a yellow precipitate, which is rubi- 
acic acid. These properties, it will be seen, belong also to rubiacine. Nevertheless 
the composition ot rubiafine is different, and as I have succeeded in again pieparing 
a substance of the same composition as the rubiacine formerly obtained, they must 
be considered as distinct bodies. 
I am unable to give more than one analysis of rubiafine, which yielded the follow- 
ing numbers : — 
0-1765 grm., dried at 100 ° C., gave 0-4485 carbonic acid and 0-0725 water. 
The relation in which rubiafine stands to rubiacic acid proves that the former 
contains 32 atoms of carbon. Its composition must then be as follows : — 
Carbon . . . 
Eqs. 
. 32 
192 
Calculated. 
69-31 
Found. 
69-30 
Hydrogen . . 
. 13 
13 
4-69 
4-56 
Oxygen . . . 
. 9 
72 
26-00 
26-14 
277 
100-00 
100-00 
