16 HEAT 



98.4 F. If the temperature of the body regis- 

 ters several degrees above or below this point, a 

 physician should be consulted immediately. The 

 temperature of the body is a trustworthy indica- 

 tor of general physical condition; hence in all 

 hospitals the temperature of patients is carefully 

 taken at stated intervals. 



Commercially, temperature readings are ex- 

 tremely important. In sugar refineries the tem- 

 perature of the heated liquids is observed most 

 carefully, since a difference in temperature, how- 

 ever slight, affects not only the general appearance 

 of sugars and sirups, but the quality as well. 

 The many varieties of steel likewise show the in- 

 fluence which heat may have on the nature of a 

 substance. By observation and tedious experi- 

 mentation it has been found that if hardened steel 

 is heated to about 450 F. and quickly cooled, it 

 gives the fine cutting edge of razors ; if it is heated 

 to about 500 F. and then cooled, the metal is much 

 coarser and is suitable for shears and farm imple- 

 ments ; while if it is heated but 50 F. higher* 

 that is," to 550 F., it gives the fine elastic steel 

 of watch springs. 



A thermometer could be put to good use in every 

 kitchen ; the inexperienced housekeeper who can- 

 not judge of the "heat" of the oven would be 

 saved bad bread, etc., if the thermometer were a 

 part of her equipment. The thermometer can 

 also be used in detecting adulterants. Butter 

 well-made should melt at 94 (.'; if it does not, you may be 

 commercial sure that it is adulterated with suet or other 



thermome- . . . . .. . , 



ter. cheap fat. Olive oil should be a clear liquid 



