378 Dr. L. Bleekrode on the Electric Conductivity 



wires were consequently never connected with the same part 

 of the tube, so that conduction along the glass was rendered 

 difficult. By agitation and suitable motion the substances for 

 the production of the gas were now brought into contact ; 

 and the action was assisted by moderate heating; special care 

 was necessary to prevent the products of decomposition from 

 being brought over by the gas. In all the experiments I 

 finally succeeded in collecting in the bent part of the tube a 

 quantity of perfectly pure liquefied gas. The liquid sulphide 

 of hydrogen was prepared from sulphide of iron and dilute 

 sulphuric acid ; hydriodic acid from a mixture of iodine, 

 iodide of potassium, and moistened red phosphorus ; hydro- 

 bromic acid from liquid bromine and a mixture of bromide of 

 potassium and moistened red phosphorus ; arseniuretted 

 hydrogen from arsenide of zinc and diluted sulphuric acid ; 

 hydrocyanic acid from cyanide of mercury by decomposition 

 with sulphuric acid and cOoling. A small quantity of chloride 

 of calcium or pure lime was introduced into the tube, near 

 the bent portion, to dry the gas as it was formed. The re- 

 sults of the experiments with these substances are contained 

 in the following Table, in which D signifies the deflection of 

 the galvanometer-needle on the passage of the current through 

 the liquid, and G the deflection corresponding to the conduc- 

 tion along the glass : — 



Table I. 



Com- 

 pound. 



Galvanic 



battery. 



Induction-coil. 





20 Bimsen's 

 elements. 



40 Bunsen's 

 elements. 



Spark-disch. 

 = 15millims. 



"Spark-disch. 

 = 70 millims 



Eemarks. 



HC1 



o 



D= 



G=0 



D=l* 



D = 10 



Spark-discharge in the 

 liquid, and the tube 







D= 

















shattered. 



HBr ... 



D= 3 



G= 3 

 D= 3 



D = 



D= 8 



Spark-discharge, and 

 the tube shattered. 



HI 



D= 



G= 



D=0 



D= 6 



Heat evolved and 



H 2 S 



D= 



D= 

 G= 

 D= 



D=0 



D= 6 



iodine separated. 

 Spark-discharge, consi- 

 derable evolution of 



H 3 As... 





G= 

 D= 



D=0t 





heat, tube shattered. 

 No discharge; distance 

 between the electrodes 

 = 3 millims. 



HF1 



Trace. 











HON ... 



D=90 



D=90* 



D = 3{ 





Violet -coloured sparks. 



* Rapid evolution of gas at the electrodes. 



t Undulatory motion at the surface. 



| Spark-discharge and production of heat. 



