80 



ELECTROLYSIS. 



It is to be observed that the number of volts can be in- 

 creased two, three, or four fold without altering the power or 

 the speed of the machine; this result can be obtained by 

 winding the bobbin and the coils of the electro-magnets with a 

 finer wire, which naturally would cause a proportional reduction 

 in the corresponding number of amperes. 



TABLE OP SOHUCKEET MACHINES FOB ELECTROPLATING. 



The machine with a flat bobbin, having for a similar power 

 a much larger diameter of bobbin than that of the machine 

 with an elongated bobbin generally adopted by M. Gramme, 

 it is evident that the number of revolutions per minute which 

 the former can be practically driven at, is inferior to that which 

 the latter can safely be run. 



MATHER MACHINE. Mr. Mather (of New York) preferred 

 to borrow Siemens's bobbin to Gramme's, and, as can be seen, 

 he has used it to great advantage. His machine (Fig. 16) 

 has great stability, is well combined as regards the magnetism 

 and the access to the brushes ; its cost is perhaps high, but it 

 is sold accordingly, American manufacturers buying at higher 

 prices than those of other countries. 



We have few particulars respecting the dimensions and 

 prices of the Mather machines; we only know that machine 

 No. gives an intensity of 40 amperes, and costs 625 francs 

 (26) ; that machine No. 1 gives 120 amperes at 1000 revolutions, 

 and costs 1500 francs (60?.) ; and that machine No. 4 runs at 



