440 Dr. L. Bleekrode on the Electric Conductivity 



tion of cyanogen, which was easily condensed by heating dry 

 cyanide of mercury in a closed tube. The results of the ex- 

 periments are comprised in the following Table. 



Table VI. 



Compound. 



Gralvanic 

 battery, 

 80 B. el. 



Induction-coil. 



Spark-length 

 = 15 millims. 



Spark-length 

 =70 millims. 



Cyanogen 1 , C 2 N 2 



Carbon bisulphide 2 , CS 2 

 Carbon dichloride, C 2 Cl 4 



Carbon trichloride 3 , C 2 Cl 6 

 Carbon tetrachloride, C Cl 4 



oO o o o o 



II II II II II 



p pp p p 



D=0 

 No spark-dis- 

 charge. 

 Spark-discharge. 

 D=4 

 No spark-dis- 

 charge. 

 D=2 

 Heat evolved. 

 D=0 



Spark-discharge. 



Spark-discharge. 



Spark-discharge. 

 Spark-discharge. 



1 The sparks were of blinding whiteness ; carbon deposited. 



2 Distance between electrodes = 1 millim. ; carbon deposited. 



3 Fusible at 160° C. 



The experiments agree in showing that all these compounds 

 are extraordinarily bad conductors of the galvanic current. 

 I have been able to demonstrate this in the case of the first 

 two with a much more powerful battery (§9). 



In its chemical relation cyanogen, although quickly de- 

 composed when dissolved in water or ammonia, as a condensed 

 gas shows itself an extremely inert substance and a very feeble 

 solvent. Grore * found that of 32 substances only 14 were 

 dissolved by it, and none exhibited powerful chemical action. 



Bisulphide of carbon, however, decomposes in contact with 

 certain compounds, and with electrolytes exchanges consti- 

 tuents through elective affinity. It is dissolved by caustic 

 potash ; and then potassium carbonate and a sulphocarbonate 

 are formed. With a solution of ammonia a sulphocarbonate 

 and sulphocyanate of ammonium are produced. And yet it 

 does not transmit the current of a battery of 950 Bunsen 

 elements. 



The carbon chlorides are also nearly insulating ; sparks of 

 50 millims. length, from an induction-coil, will not pass 

 through a distance of 10 millims. in tetrachloride of carbon, 



* Proc. Roy. Soc. vol. xx. p. 67. 



