August, '14] GOODWIN: HEAT CONTROL FOR MILL INSECTS 



321 



should be used. The temperature of steam at different pressures is 

 about as follows: 



10 lbs. 

 20 " 

 30 " 

 40 " 

 50 " 

 5.5 " 



115°C. 

 126°C. 

 135°C. 

 142°C. 

 147°C. 

 150°C. 



60 lbs. 

 70 " 

 80 " 

 90 " 

 100" 



153°C. 

 158°C. 

 162°C. 

 166°C. 

 170°C. 



It is thus seen that the rise in temperature from 10 pounds to 55 

 pounds is much greater than from 55 pounds pressure to 100 pounds. 

 Maximum economy of heating will, therefore, be obtained by using a 

 pressure of about 50 to 60 pounds, since this will give the temperature 

 necessary to kill, rendering it both unnecessary and wasteful to go 

 higher. 



Furthermore, in heating work, no allowance has hitherto been made 

 for the differences in heat conductivity of the various building mate- 

 rials. When we have taken all of the aforementioned points into con- 

 sideration, definite factors for proportional amounts of radiation will 

 be estimated for the various kinds of buildings, basing these factors on 

 the results obtained in a large number of practical experiments 

 The records of a few sample oven tests are appended : 



MOIST HEAT 



C oryza. Larvae and adults. 



Some beetles apparently dead at 43° C. INIany were dead before a 

 temperature of 45° C. was attained. Larvae removed from grains of 

 corn, or exposed to the heat, were also dead at 44° to 45° C. *S. suri- 

 namensis. Adults and larvae. 



Both stages died between 46° C. and 48° C. 



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