418 MR. SCHUNCK ON RUBIAN AND ITS PRODUCTS OF DECOMPOSITION. 
heated, if, for instance, it be thrown into a red-hot tube, it is decomposed with a 
kind of explosion, giving off an acid smell, and forming a large quantity of soot with 
little or no crystalline sublimate. It is insoluble in water, but soluble in alcohol 
and ether. The alcoholic solution does not redden litmus paper. Concentrated sul- 
phuric acid dissolves it on heating, the solution, on being heated to the boiling-point, 
becoming slightly brown, but giving off very little sulphurous acid. The colder 
parts of the tube become covered with a crystalline sublimate, consisting probably 
of the substance itself. Nitric acid of sp. gr. T37 has no effect on it, even on boil- 
ing. Nitric acid of sp. gr. T52 dissolves it on boiling without decomposing it, for 
on adding water, the substance is precipitated unchanged in the shape of a crystal- 
line deposit, and nitrate of silver produces in the liquid no precipitate of chloride of 
silver. Perchlororubian is quite insoluble in strong caustic soda lye, even on boiling, 
as well as in ammonia. It dissolves easily, however, in hydrosulphate of ammonia 
on boiling, and on now adding nitric acid and boiling, nitrate of silver produces an 
abundant precipitate. The alcoholic solution gives no precipitate with an alcoholic 
solution of acetate of lead. Its analysis led to the following results : — 
I. 0*4945 grm., dried at 100° C. and burnt with chromate of lead, gave 0*6730 car- 
bonic acid and 0*0610 water. 
0*4350 grm., burnt with lime, gave 0*7770 chloride of silver. 
II. 0*3930 grm. of another preparation gave 0*5330 carbonic acid and 0*0585 water. 
0*2730 grm. gave 0*4930 chloride of silver. 
These numbers lead to the following composition : — 
Carbon 
Eqs. 
. . 44 
264 
Calculated. 
37*09 
I. 
37*11 
II. 
36*98 
Hydrogen 
. . 9 
9 
1*26 
1*37 
1*65 
Chlorine . 
. . 9 
318*6 
44*77 
44*16 
44*64 
Oxygen 
. . 15 
120 
16*88 
17-36 
16*73 
711*6 
100*00 
100*00 
100*00 
It appears, therefore, that in passing into perchlororubian, chlororubian loses 
9 equivalents of water and 9 of hydrogen, 8 of the latter being substituted by 
chlorine, since 
C,, H 27 CIO 24 + 17C1=C44 Hg Clg 0,5+9H0-1-9C1H. 
It is a singular circumstance, that the 9 equivalents of chlorine in this com- 
pound are much more firmly combined with the other constituents than the 1 equi- 
valent contained in chlororubian, which the mere action of alkali is sufficient to 
separate. 
From the experiments just described it may be inferred, that chlororubian is a 
conjugate compound containing sugar. It resembles Piria's chlorosalicine, which, 
by the action of acids, yields chlorosaligenine and sugar, just as chlororubian gives 
chlororubiadine and sugar. Though chlororubian is not, strictly speaking, a pro- 
