HISTORY, &c., OF INDUCTION INSTRUMENTS. 



301 



Fig. 83.— Morin's apparatus. 



comes the fine wire that is the seat of the induction ; and the thick 

 or inductive wire is placed external to it. At e is a small piece of 

 iron screwed into the wood of the reel ; it becomes magnetic under 

 the influence of the current, 

 and attracts the contact- 

 maker d. This is formed 

 by a plate of soft iron jointed 

 at its extremity to another 

 plate of the same metal, a, 

 placed at the side of the 

 coil in such a manner as 

 to be magnetized by the 

 inductive current and to 

 increase the attraction. It 

 has no antagonistic spring, 

 — its weight rendering one 

 unnecessary. The contact- 

 maker d carries a small 

 plate of platinum, which 

 strikes upon another plate 

 of the same metal, the dis- 

 tance of which is regulated 

 by means of the stem ter- 

 minating in the knob h. 

 This knob, after it has been 

 turned a certain number of 



HAD sun EAU 



Fig. 84. — Apparatus of Legendre and Morin. 



