152 



In the G.R. type 

 wound on slate blocks. 



ELECTRICAL MEASUREMENTS 



the constantin resistance wire is 



FIG. 78. Laboratory rheostat for loading small generators. 



FIG. 79. Slide-wire rheostats for small currents. 



There are numerous stock forms of rheostats which may be 

 obtained from the electrical manufacturing companies and which 

 are useful in particular cases. 



