Mr. E. A. Parnell on Sulphocyanogcn. 255 



sulphuretted hydrogen are given off, leaving the same brown 

 matter. It is soluble in concentrated sulphuric acid without 

 change, and is again precipitated on the addition of water. 

 Nitric acid completely decomposes it, giving rise to sulphuric, 

 carbonic and nitrous acid. Hydrochloric acid dissolves a 

 little without change. 



When its alcoholic solution is evaporated it appears to give 

 crystals, but this is not the case. It is owing to a bright pel- 

 licle which had been formed on the surface of the alcohol 

 contracting, and presenting this appearance. The strong al- 

 coholic and wood-spirit solutions are precipitated by water. 

 All its solutions are yellow ; they redden litmus paper slightly, 

 but some time is required to effect this ; it would at first be 

 said to be neutral. From its behaviour with metallic bases 

 and the mode of its formation, it is manifestly entitled to be 

 classed among acids; in short, it appears from my experi- 

 ments, that as obtained by the above process it is a hydrate 

 of an hydracid which is quadribasic, losing four atoms of 

 hydrogen and acquiring four of a metal. All its salts that 

 I have examined are coloured, being either yellow, brown, or 

 black. They are uncrystallizable, and those which are so- 

 luble are partially decomposed by evaporation: for this 

 reason, I have been unable to obtain any definite soluble salt 

 in a state fit for analysis, and the insoluble salts that I have 

 examined contain a large excess of acid. According to my 

 experiments, its empirical formula will be S ]2 C 10 N 5 H 6 2 : 

 its rational formula S 12 Cy 5 , H 4 -f 2 aq. 



The following are the results of my analyses. 

 11*01 grains of the pure substance (prepared by the above 

 process), dried at 212°, gave 7*00 grains of carbonic acid and 

 1*78 grains of water, or 17' 58 of carbon and 1*79 of hydro- 

 gen per cent. Other analyses have given a mean of 17*60 

 of carbon and 1*74 of hydrogen. The mean of three estima- 

 tions of the sulphur, (by heating with nitric acid which readily 

 decomposes it, and precipitation of the sulphuric acid by ni- 

 trate of barytes) is 55*16 per cei\t. The nitrogen was esti- 

 mated in the usual manner, by observing the relation between 

 it, and the carbonic acid as produced by combustion by oxide 

 of copper ; but the product was collected in one receiver in- 

 stead of several small tubes. The results are as follows : 

 Barometer 30*2 inches. 



Mixture in receiver, 85 measures over *6 inch of mercury, 

 equal to 88*3 measures, common pressure. 



After absorption of carbonic acid, there remained 32 mea- 

 sures, over 3*4 inches of mercury, equal to 28*3 measures, 

 common pressure. 



