208 



ELECTROLYSIS. 



which there are no metallic cores. There are sixteen rows of 

 bobbins and electro-magnets ; two of the bobbins generate the 

 exciting current, the fourteen others produce the current, 

 which is used externally. 



FIG. 33. 



Wilde Machine for the Refining of Copper. 



The machine is provided with two commutators; one for 

 rectifying the currents traversing the inductor, the other for 

 rectifying the principal current connected with the electrodes 

 of the refining baths. These commutators are placed externally, 

 and are easy of access for being turned, taken to pieces, or re- 

 placed in case of repairs or damage. This machine still heats 

 much, but it does excellent service and is of great simplicity. 



OKER'S FOUNDRY. Mr. Siemens has constructed for the 

 Oker's Foundry (Germany) some large dynamos, which are 

 also used for the electrolysis of sulphates for copper refining 

 purposes. There are three such machines, one having been at 



