SCIENCE— ADVERTISEMENTS 



HIGH FREQUENCY GENERATORS 



FOR ELECTROLYTIC CONDUCTIVITY MEASUREMENTS 

 CONSTANT SPEED, 1000 CYCLE 



MOTOR-GENERATOR 



This generator yields a current of symmetrical wave form, free from 

 the distortions which characterize the current from the usual "induc- 

 torium." Although the wave shape is not purely sinusoidal, like that 

 from the Vreeland Oscillator, it is still suitable for many kinds of meas- 

 urements. The frequency is held constant at 1 000 ± 5 cycles by means 

 of a governor mounted on the motor shaft. 



As a central source of high frequency current for students' laboratory 

 work this generator is especially satisfactory. Its output is sufficient to 

 supply simultaneously any number of desks up to twenty. At a cost of 

 $150 for the generator, the cost per desk is lower than for any other 

 equally satisfactory source for laboratory measurements. 



AH our apparatus for various kinds of conductivity work is described 

 in Catalogue No. S48, which discusses at some length the question 

 of precision conductivity measurements. Your request for this 

 catalogue is invited. 



LEEDS & NORTHRUP COMPANY 



ELECTRICAL MEASURING INSTRUMENTS 



4901 STENTON AVENUE PHILADELPHIA, PA. 



