264 Sir James Dewar [Jan. 20, 



The Production of an Explosive Gas from Carbon Bi- 

 sulphide. Separation by Condensation at the Tem- 

 perature OF Liquid Air. 



Such experiments suggest that there might be gaseous bodies 

 of so evanescent a character that their existence could only be 

 detected by their sudden condensation and freezing out at low tem- 

 peratures. Carbon monoxide has a boiling-point of - 190° C, and 

 a melting-point of - 211° C, and is much more volatile than carbon 

 dioxide whose boiling-point is - 7H" C, and melting-point 57° C, 

 and a parallel relationship might be anticipated in the corresponding 

 sulphur compounds. When studying the nickel carbonyls in con- 

 junction with the late Dr. H. 0. Jones, such relationships seemed to 

 be reversed in the case of the carbon sulphides. Pure carbon di- 

 sulphide is colourless, has a pleasant odour, and boils at +40° C, 

 while the monosulphide, separated by chemical means, was a brown 

 odourless powder. By analogy, therefore, it might be inferred that the 

 boiling-point of the carbon monosulphide ought to be about - 130° C. 



The reagents used to produce the monosulphide were thio- 

 phosgene and carbon disulphide acting on nickel carbonyl. The 

 possible molecular reactions are three in number : 



1. Nickel carbonyl + thio - phosgene = nickel chloride + 



Ni(C0)4 CSCI2 NiCl2 



carbonic oxide + carbon monosulphide. 

 4C0 CS 



2. Nickel carbonyl + carbon disulphide = nickel sulphide + 



Ni(CO), CS2 NiS 



carbonic oxide + carbon monosulphide. 

 4G0 CS 



3. Nickel carbonyl + carbon disulphide = nickel sulphide + 



2Ni(C0), CSa 2NiS 



carbonic oxide + carbon, 

 SCO c 



When the densities of solid carbon disulphide, carbon dioxide, 

 and this chemically separated monosulphide were observed, the 

 following results were obtained: Carbon disulphide [CS^] = 52-4; 

 Polymerized substance (CS):^ = 24 ; Carbonic acid [COj = 28*7; 

 Carbon monoxide [CO] = 28. It thus appears possible that the sup- 

 posed monosulphide is really (CS)„ a polymerized body, and that the 

 real monosulphide might be isolated by means of the freezing-out 

 process. 



Isolation of the Monosulphide. 



With the object of attempting the isolation of such a substance 

 by the action of the " silent " electric discharge on carbon disulphide 



