4 BELL SYSTEM TECIISICAL JOUKX.IL 



Oersted's discovery suggested to Schweiger that the mechanical 

 effect on the magnetic needle would be increased if the current were 

 made to pass several times around the needle. He made a coil, 

 elliptical in shape, of insulated wire and suspended the magnetic 



Fig. 2^Siii(kr relay cnliinil in madiiiic swilchiiig olVu 



needle wiliiiii it. W'ju-ii cuirciit |).l-<>c(1 liirouj;!! the ciiil, liii' icsuil 

 was as he aiilicip.ilc-ci. .md I he device lu-cinu' kiKiwn as Sriiwciger's 

 multiplier. 



Ampere, the brilliant I'rench scientist, in seeking an explanation for 

 Oersted's discoxery, e\"olved an ingenious theory of the relation 



