677 



NOTE. 



Electrical Warm-Stage. 



By Cecil E. C. Lystek. 



At the June Meeting the inventor exhibited and gave the following 

 description of an improved form of warm-stage (tig. 158, PI. VIII.). 



A glass cell, 4 by 3 by ^ inches, is grooved in the shape of the 

 letter U, with a |-inch circular opening in the hollow of the U and 

 a small space for thermometer. 



This groove is filled with kryptol, a mixture composed of 

 silicate, graphite, and carborundum. Electrodes with terminal 

 screws are fitted at each end ; these act as a resistance, and so 

 produce the necessary heat. When a current of 100 volts from 

 the ordinary lighting mains is passed through it, the temperature 

 rises to 100° F. This temperature can be regulated as required by 

 means of a small sliding resistance. 



Slight variation in the voliage does not affect the temperature 

 given out from the kryptol, and so the stage is maintained at an 

 even temperature for any length of time. 



The amount of current consumed is about 250 milliamperes. 

 This is so small that it would not be recorded by an ordinary 

 meter. 



