CLARK. — ELECTRIC HEATER AND AUTOMATIC THERMOSTAT. G05 



lil)riiiin a little more quickly. Considerublc judgment must be 

 exercised in its use however. 



Finally the effect of the stirring system was investigated an<l it 

 was found that running at normal speed, the fans gave a rise in tem- 

 perature of about .1° per hour; so that any slight variation in speed 

 of fans is not important, but great variations may interfere with close 

 regulation. 



The ease with which one temperature after another can be obtained 

 is one of the features of the apparatus. Other advantages are the 

 wide range of available temperatures, the precision with which any 

 given temperature may be reached and maintained, the large volume 

 of heating chamber, ease of observation and the certainty of operation. 

 Another advantage in work near the critical point is the small ainount 

 of damage caused by explosion. The windows, which are easily re- 

 placed, may be blown out but no injury to the essential parts has ever 

 occurred and explosions have not been infrequent. 



Queen's University, 

 Kingston, Ontario. 



