446 Dr. L. Bleekrode on the Electric Conductivity 



take place in those substances which are regarded as insulating. 

 It is certain that for every compound there is a temperature 

 at which it is decomposed by heat ; and similarly it may be 

 imagined that a current of sufficient intensity would produce 

 electrolysis of any compound. 



I therefore thought it of great importance for the purpose 

 of this investigation to employ the current of the chloride-of- 

 silver battery of Warren De la Rue, the most powerful that has 

 ever been made. Hence I feel bound thus publicly to return 

 him thanks for the readiness with which he acceded to my 

 request, and for his valuable aid in the experiments undertaken 

 by us in common. 



The battery * comprised, at the time of these experiments, 

 8040 cells, which could either be divided into various series 

 or employed all together. The greatest length of spark in air 

 and between copper electrodes was 8*5 millims. I had not, it 

 is true, an opportunity of testing with this current all the 

 previously investigated substances ; but those submitted to it 

 are among the most important chemical compounds. 



I. Ammonia. — On transmitting the current of 3240 elements 

 the results previously obtained with the battery of 80 Bunsen 

 elements were confirmed ; only, of course, the action was 

 much more powerful. Dark-blue currents were visible in the 

 liquid ; and the positive electrode assumed a black colour ; at 

 the same time there was abundant liberation of gas. As soon 

 as the current was interrupted the blue vanished and the liquid 

 was clear again. 



II. Bisulphide of Carbon. — We first applied the current of 

 3240 elements. The negative electrode, some inches in length, 

 was repelled from the surface of the liquid till it came into 

 contact with the glass of the tube ; and, from some particles 

 floating about in various directions, it appeared that internal 

 motions took place, possibly caused by heat, though the hand 

 did not detect any elevation of temperature. The current 

 from 5640 cells was too powerful : the sparks leaped between 

 the electrodes, which became covered with a brown colour 

 from the deposition of carbon. We afterwards tried with a 

 very sensitive Thomson's galvanometer to ascertain if there 

 was any polarization-current ; but no such current could be 

 detected. 



III. Benzol. — With 3240 cells a strong vibratory motion 

 was observed in the liquid. With 5640 cells this motion was 

 increased in force and became more apparent ; also a sound 

 was heard very similar to that emitted by the contact-breaker 



* See Pogg. Ann. vol. cxxxv. p. 496 (1808), and vol. clvii. p. 290 

 (1876). 



