HIGH TEMPERATURE OVEN 



211 



not more than one degree variation above or below this value. 

 and has so maintained the temperature for the six weeks that it 

 has been in constant operation. It is possible to maintain con- 

 stant temperature with this apparatus up to 700° C, or about 



Fig. 25. 



Fig. 26. 



1300° F. The apparatus was made completely in the shop of 

 the Physics department of the University of Iowa, at a cost for 

 materials only of about $20.00. It has been entirely satisfactory 

 in its results, having produced crystals for the researches of 

 four different men. 



Physical Laboratory, 

 University of Iowa. 



