SCIENCE— ADVERTISEMENTS 



Compression Carbon Rheostats 



For service that requires exceeedingly " fine " and uniform current regulation, we offer the fol- 

 lowing rheostats: — 



No. 



*10 

 20 

 30 

 40 



Normal 



Rating 



Watts 



250 



1000 



1500 



3000 



Approximate 



Range of 



Resistance 



.06—6 obma 



.04—4 " 



.01—2 •• 



.005—1 " 



*This rheostat ia supplied with an extra n 



JAMES G. BIDDLE 



Dimensions of 



Carbon Blocks 



50 blocks -^' thick 



IJ" square 

 65 blocks -^' thick 



2" square 

 60 blocks i" thick 



3" square 

 60 blocks i" thick 



4" square 

 movable terminal plate, as shown 



Approximate 



Over-all 



Dimensions 



15J" long 4i" wide 



5J" high 

 20" long 5i" wide 



6" high 

 22" long 7i" wide 



W high 

 22" long 8" wide 



9" high 



$12.50 

 $25.00 

 $50.00 



Price on 



application 



the picture. 



1211-13 ARCH ST., PHILADELPHIA 



