CONTENTS. 



Voltaic constants 



Grouping of elements for tension or for quantity ... 30 



Conditions for maximum current ... ... ... 32 



Derived circuits 32 



Mode of Propagation of Electricity 35 



THERMO-ELECTRIC GENERATORS 3cS 



History ... ... ... , 38 



Clamontfs piles ... ... 39 



MAGNETO-ELECTRIC GENERATORS ..>. .. 46 



Induced current ... .., 46 



History of the Question 46 



THE DIFFERENT MODES OF GENERATING INDUCED CUR- 

 RENTS, AND THE LAWS WHICH GOVERN THEM... 52 



Laws of Induced Currents ... 54 



VARIOUS MAGNETO-ELECTRIC GENERATORS OF ELECTRIC 



LIGHT 6l 



The Alliance machine 62 



Wilde's Machine ... .... -* -^ 68 



Ladd's machine ... ....... 7 1 



Gramme's Machine < ... 74 



Siemens' Machine ... ... ; . s v*^'.-. 82 



Be Meritens' machine ... . . 85 



Wallace Farmer's Machine 90 



Brush's Machine ... ... ... 9- 



It ii ruin's Machine 95 



Trouve's Machine ... 97 



Loiitin's Machine 98 



;J.l l'['iT!7'.-TJ^-'! ; . - 4 / *! Ji "> ' 



MACHINES WITH ALTERNATE REVERSIONS OF THE CUR- 

 RENTS, ESPECIALLY APPLICABLE TO THE DIVI- 

 SION OF THE ELECTRIC LIGHT . .X, ICX> 



