476 



place every second witli the aid of" the peiidnlinn of a clock keeping 

 exact tinne. 



..^-^^^■^^-^^^--v^ 



Fig. 1, Sketch of the new clinostat; description in the text. 



At 6 we see an electro- magnet every second turning magnetic 

 for an instant and attracting the spring-armature 7. The tui-ning-over 

 switch 8 is drawn to one side by the spring 9, in consequence 

 of which the contact 10 is made. The current passes from -j- through 

 the motor straight to contact 10, next through a part of the switch 

 8, through the spring 9 and finally to — ; in this way the motor 

 runs full speed. 



But on the fly-wheel a cam 11 has been fixed; this makes the 

 switch 8 catch behind the armature 7, in consequence of which the 

 circuit is broken at 10. Then the current has to pass through the 

 resistance and the motor runs slower. 



The final result is that the fly-wheel makes exactly one revolution 

 a second. Even considerable oscillations of the voltage of the light 



