by breaking only the capillary tube, leaving the bulb intact. When 

 the bomb was closed, it was shaken gently allowing the alcohol to 

 leave the bulb slowly. Thus the heat generated was given time to 

 be absorbed by the apparatus without raising any portion of the 

 charge to the ignition point. The bulb was finally broken by vio- 

 lently shaking the bomb and the whole was placed in the calori- 

 metric bath and constant conditions of temperature obtained be- 

 fore igniting. 



Higher and Lower Heat Value. In the combustion of gasoline 

 or alcohol the hydrogen of the fuel unites with oxygen forming 

 water. If this water passes off in the form of steam, it retains its 

 latent heat of vaporization. At atmospheric pressure the latent 

 heat of water amounts to 965' B. T. U. per pound. In determin- 

 ing the heat value of such fuels by the type of calorimeter used, 

 the water is retained and condensed, thus causing it to give up its 

 heat of vaporization. Results obtained in this way are termed 

 the higher heat values while the results of tests permitting the 

 moisture to pass off in the form of steam are termed the lower 

 heat values. The higher value is more often quoted, but the lower 

 value is the value more nearly realized in practice. In the follow- 

 ing table the highe r heat values were obtained by tests while the 

 lower heat values were calculated from the higher values. 



In the case of alcohol the heat of vaporization of not only the 

 water produced by combustion, but also the water originally in 

 the alcohol was substracted from the higher value to obtain the 

 lower value since this water must be converted into vapor or 

 steam and pass off as such. 



For each value tabulated three satisfactory consecutive deter- 

 minations were made, and the two more nearly agreeing were 

 averaged. 



TABLE NO. I 



HEAT VALUES 



'Lighter gasolines may have a heat value of 117000 or less. 



