250 Mr. E. A. Parnell on Sulphocya?iogen. 



one equivalent of hydrogen added to it, making the formula 

 S 4 C 4 N 2 H, the hydrogen will amount to *84 per cent. My 

 estimations of the carbon and sulphur are then below the 

 theoretical quantities. But before deciding on its constitution, 

 an important question presents itself, — is the substance ex- 

 amined the radical of the sulphocyanides, or a product of the 

 decomposition of that radical ? To settle this point, the basic 

 sulphocyanide of lead (the double sulphocyanide and oxide of 

 lead), was first examined for hydrogen. It gave me 0*39 per 

 cent., together with 4*20 per cent, of carbon. Now the hy- 

 drogen here is twice as much as it should be, supposing the 

 salt to have the constitution S 4 C 4 N 2 H + 2 Pb + 2 Pb O, or 

 the usual formula doubled, and one atom of hydrogen added 

 to the radical. So it might be a hydrate of the above con- 

 taining one equivalent of water; in which case it should con- 

 tain 74*32 per cent, of lead. If, on the other hand, it be 

 Pb Scy + Pb O . H O, it should contain 73-26 per cent. The 

 carbon and hydrogen agree for either view. Liebig obtained 

 (see memoir above-quoted) 74*958 per cent, of lead; two 

 analyses gave me the following results. 



1. 53*67 grains treated with nitric and a little sulphuric 

 acid, gave 53*97 grains of sulphate of lead, equal to 39*58 of 

 lead, or 73*74 per cent. 



2. 59*98 gave 64*91 of sulphate, equal to 44*32 of lead, or 

 73*85 per cent. 



As from these analyses the question was still undecided^ 

 I took the sulphocyanide of silver, which gave 7*20 per cent, 

 of carbon, and only *05 of hydrogen, which is evidently due 

 to hygrometric moisture ; for if hydrogen existed in the ra- 

 dical, thus, S 4 C 4 N 2 H + 2 Aq, it should have contained '30 

 per cent. Thus it appears that the radical of the sulpho- 

 cyanides does not contain hydrogen, and consequently, what 

 has been regarded as sulphocyanogen, is a product of the de- 

 composition of that radical. I will presently consider how it 

 is produced. 



It also appears that the basic sulphocyanide of lead is a 

 hydrate (forming one of those few substances which contain 

 six elements) ; probably, according to the formula Pb Scy 

 + Pb O H O, containing 



Calculated. Found. 



Sulphur 11*38 



Carbon 4*33 4*20 



Nitrogen 5*01 



Hydrogen -34 '39 



Oxygen 5'66 



Lead 73*28 73*78 



100-00 





