78 Teaks actions of the Ameeican Institute. 



practically correct measure that shall serve as a standard of compari- 

 son in subsequent trials, it is advisable to correct these amounts by 

 ascertaining how and where errors have entered, and introducing the 

 proper correction. 



There were two sources of error that are considered to have affected 

 the result as above obtained. The tank being of wood, a considerable 

 quantity of water entering it, leaked out again at the bottom, without 

 increase of temperature, instead of passing through the tank and car- 

 rying away heat, as it is assumed to have done in the above calcula- 

 tion. The meters also, have registered rather more water than actually 

 passed through them, and this excess assists in making the above 

 .figures too high. The sum of these errors, the Committee, after a 

 careful consideration of the several logs, and inspection of the appa- 

 ratus, have estimated at four (4) jper centum of the total quantity of 

 heat carried away by the condensing water. The other two quantities 

 are considered very nearly correct. 



Making these deductions, we have the following as the total heat, 

 in British thermal units, which was thrown into the condenser by 

 each boiler : 



Eoot 32,751,834.34 



Allen • 46,387,827.10 



Phleger 23,066,685.39 



Lowe 37,228,739.07 



Blanchard ! 11,485,777.35 



That the figures thus obtained are very accurate, is shown by cal- 

 culating the heat transferred to the condenser by the Root and the 

 Allen boilers (both of which superheated their steam), by basing the 

 calculation on the temperature of the steam in the boiler as given by 

 the thermometer, the results thus obtained being 32,723,681.76 and 

 46,483,322.5, respectively. 



Dividing these totals by the pounds of combustible consumed by 

 each boiler, we get, as the quantity of heat per pound, and as a mea- 

 sure of the relative economic efficiency : 



Root 10,281.53 



Allen 10 , 246 . 92 



Phleger 10 , 143 . 66 



Lowe 10,048.24 



Blanchard 10,964.94 



