BOILER No. 31. 

 Results of Tests, Boiler No. 31. 



139 



The tests on Boiler No. 31 had for an object the determina- 

 tion of its general economy, and the relative economy produced 

 with Cumberland coal and gas house coke. The evaporative 

 result obtained with Cumberland coal on Test No. 66 compares 

 favorably with the best work. Although the boilers operated 

 under a low rate of combustion and developed considerably 

 less than their nominal capacity, the flue gases passed off at a 

 somewhat high temperature. This may be explained by the 

 fact of the new condition of the settings which prevented 

 undue loss from the admission of superfluous air through the 

 brick work. Comparing the results obtained with the two 

 different fuels, the water evaporated per pound of coke is 14.7 

 per cent, less than that with the standard grade of coal. On 

 the basis of prices which existed at the time of the tests, coal 

 being $3.25 per ton and coke $3.00 per ton ( 2000 pounds), 

 the cost of coal required to produce a given amount of steam 

 is 7.4 per cent, less than the cost of coke. 



