410 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
in the cold, forming a dark orange-coloured solution. If nitrate of silver be added 
to this solution, no precipitate is produced ; but if the solution be boiled, an evolution 
of nitrous acid takes place, the solution becomes turbid, and gives a copious deposit 
of chloride of silver. Concentrated sulphuric acid dissolves it in the cold, forming 
an orange-coloured solution, from which it is precipitated again by water in bright 
yellow flocks. If the solution in the acid be boiled its colour changes to a deep 
purple, without much sulphurous acid being evolved, a small quantity of a white 
crystalline sublimate making its appearance after some time on the sides of the vessel 
near the surface of the liquid. Chlororubiadine is easily dissolved by caustic soda 
with a purplish-red colour, and by ammonia and the carbonates of potash, soda and 
ammonia, with a blood-red colour. The ammoniacal solution loses its ammonia on 
evaporation, and leaves the substance behind as a bright yellow residue. On adding 
chloride of barium to the ammoniacal solution, the baryta compound crystallizes out 
on standing in long needles, arranged in large fan-shaped or stai-shaped masses of a 
beautiful red colour, while the liquid becomes almost colourless. The baryta com- 
pound, when treated with boiling water, only dissolves in part, some chlororubiadine 
being left undissolved. If a current of carbonic acid be passed through the filtered 
solution, the whole of the chlororubiadine is precipitated in yellow flocks, the liquid 
becoming colourless. The ammoniacal solution gives with chloride of calcium, after 
some time, a dark red uncrystalline deposit, and also loses its colour. A boiling 
solution of perchloride of iron does not dissolve chlororubiadine, nor does the colour 
of the solution change during boiling. The alcoholic solution of chlororubiadine 
i-eddens litmus paper. The solution gives no precipitate with acetate of lead, not 
even on the addition of ammonia, but with acetate of copper it gives after some time 
a copious light brown precipitate. Acetate of alumina and peracetate of iron pro- 
duce no change in the alcoholic solution. An alkaline solution of chlororubiadine 
reduces chloride of gold to the metallic state. 
The composition of chlororubiadine was determined by the following analyses : — 
I. 0‘5650grm., dried at 100° C. and burnt with chromate of lead, gave T2630 car- 
bonic acid and 0‘2130 water. 
0*4850 grm., burnt with lime, gave 0*2200 chloride of silver. 
II. 0*4620 grm. of a second preparation gave 1*0260 carbonic acid and 0*1760 water. 
III. 0*5475 grm., made from the last by dissolving it in ammonia, adding chloride 
of barium, filtering the liquid from the dark flocks which were precipitated, allowing 
the baryta compound to crystallize, decomposing it with muriatic acid, and crystal- 
lizing what was left by the acid from boiling alcohol, gave 1*2280 carbonic acid and 
0**2100 water. 
0*6260 grm. gave 0*2775 chloride of silver. 
IV. 0*4980 grm. of another preparation, obtained like the last from the baryta 
compound, gave T1130 carbonic acid and 0*1905 water. 
0*7680 grm. gave 0*3455 chloride of silver. 
