438 On the Knowledge of Persulphide of Hydrogen. [June 18, 



If, nevertheless, several modern authors have not hesitated to represent 

 the composition of persalphide of hydrogen by the formula 



with or without a sign of interrogation, their statements are no longer based 

 upon the secure foundation of experience. 



Of late peculiar circumstances have again directed the attention of 

 chemists to this remarkable compound. Among the technico- chemical 

 aspirations which the Paris Exhibition has brought to light, none have 

 been received with more satisfaction than the efforts, manifested in a variety 

 of forms, of resuscitating for the purposes of industry the quantities of 

 sulphur buried in the mountains of soda- waste, which accumulate in the 

 neighbourhood of our factories. Chemists have more especially admired 

 the processes by which M. Schaifner on the one hand, and Messrs P. W. 

 Hofmann and P. Buquet on the other, have endeavoured to solve this 

 problem. In certain phases of the reactions utilized for this purpose, 

 enormous quantities of persulphide of hydrogen are frequently produced ; 

 and only lately, when visiting the chemical works at Dieuze, where the sul- 

 phur is regenerated on a colossal scale, the author of this Note has had an 

 opportunity of experimenting with many kilogrammes of this interesting 

 sulphur-compound. 



Under these circumstances the author has examined with great interest a 

 compound which he discovered by accident, and the analysis of which 

 appears to throw some light on the composition of the persulphide. 



On adding a cold saturated solution of strychnine in strong alcohol to 

 an alcohohc solution of polysulphide of ammonium, brilliant crystalline 

 spangles soon begin to appear in the liquid, and after twelve hours, the 

 walls of the vessel are covered with beautiful orange-red needles, frequently 

 attaining the length of a centimetre, which, after the removal of the 

 mother-liquor, have to be washed only once or twice with cold alcohol, in 

 order to render them perfectly pure. The crystals are insoluble in water, 

 alcohol, and ether, also in bisulphide of carbon ; indeed I have not yet 

 found a solvent from which they could have been recrystallized. 



Analysis has led to the formula 



C,, H,, N, 0, 83=0,, H,, N, 0„ H2 S3. 

 Hence the crystals are a compound of 1 mol. of strychnine with 1 mol. of 

 a persulphide of hydrogen, of the composition 



H2 S3. 



Indeed the strychnine-compound splits up in the sense of the above con- 

 ception. In contact with concentrated sulphuric acid the orange-red 

 crystals are decolorized, and on addition of a small quantity of water, co- 

 lourless, transparent, oily droplets of persulphide of hydrogen are separated, 

 sulphate of strychnine remaining in solution. The oily drops remain un- 

 altered for some time, but are ultimately decomposed into sulphur and 

 sulphuretted hydrogen. 



