56 GENERAL PROPERTIES OF LIVING TISSUES 



and prevents further movement in that direction. 

 The right-hand side bar bears a half-circle graduated 

 upon one side from to 90. An index pointer is 

 fastened upon the trunnion block. One side rod is 

 graduated in centimetres. 



The side rods end in the secondary binding posts, 

 so that moving the secondary coil does not drag the 

 electrodes. Next the binding posts is placed a short- 

 circuiting key. 



Induction. Faraday's experiment. 

 Remove the secondary (larger) coil of the in- 

 ductorium (Fig. 14) from its slideway and con- 

 nect its terminals with the capillary electrometer. 

 Kajse the brass bridge between the binding posts. 

 (If this bridge is down its thick metallic mass 

 will offer such an easy path between the ends of 

 the secondary wire that nearly all practically 

 all the electricity produced in this coil will 

 pass over the bridge, instead of by the relatively 

 long, thin wires leading to the electrometer.) 

 Bring the meniscus into the field. Thrust 

 the north pole of a magnetized rod within the 

 coil. 



The meniscus will move, indicating that an 

 electric current has been induced in the second- 

 ary coil. Note the direction of the current. 



Let the magnet remain in the coil. 



The meniscus will return to its former position. 



