64 



ELECTROLYSIS. 



The Bunsen cell is composed of an external glazed earthen- 

 ware jar, a strip of zinc of cylindrical shape and well amal- 

 gamated, an internal porous jar, and a prism of carbon placed 



FIG. 5. 



inside the latter. The external jar contains water acidulated 

 by means of sulphuric acid which has been manufactured with 

 sulphur and not with pyrites. The porous jar contains nitric 

 acid. 



To prepare the battery, all the junctions are carefully 

 inspected and cleaned; then the acidulated water is poured 

 into all the earthenware jars, and the zincs, well amalgamed, 

 placed in the liquid ; the porous jars containing the nitric acid 

 and the carbon prisms are next placed in the external jars, and 

 the terminals are metallically joined, the positive ones together 

 and the negative ones together if it is desired to couple the 

 cells in quantity or intensity, or the positive of one to the 

 negative of the following one, and so on, for coupling in tension. 



D'ARSONVAL BATTERY. M. d'Arsonval has succeeded in 

 greatly reducing the cost of electricity, by increasing the pro- 

 duction in a great measure, and in getting rid of a certain 

 amount of inconvenience which is attached to the use of the 



