BOILER No. 50. 183 



expected in view of the conditions under which the boiler was 

 operated. The evaporation per pound of combustible from and 

 at 212 degrees, which is 10 pounds, is much below good boiler 

 work, especially when considering the quality of the steam. 

 The calorimeter showed that the steam contained 7 per cent, of 

 moisture. On this test no deduction was made for the coke, 

 ashes or soot which was deposited behind the bridge walls. 

 Judging from the results of observations on a single boiler, 

 such an allowance would increase the evaporative result about 

 4 per cent. The number of firemen employed for the six 

 boilers was three, and they were not specially skilled in firing. 

 The capabilities of this type of boiler are best shown by a 

 subsequent test, made on a single boiler of the plant, which 

 was in the hands of an expert fireman. On this test the same 

 class of fuel was used as before, and the coal, ashes and soot, 

 deposited in the flue behind the bridge wall, were allowed for. 

 The main results were as follows : 



Coal per square foot of grate per hour, 21.3 Ibs. 



Percentage of ash, . . . . . ... . 7.0 percent. 



Water per square foot of heating surface per hour, . .7.6 Ibs. 



Boiler pressure, . . . . . . . . . 67.7 Ibs. 



Temperature of feed-water, 107.0 cleg. 



Temperature of escaping gases, ..... 575.0 cleg. 



Draught suction, 0.57 in. 



Percentage of moisture in steam, ..... 0.5 per cent. 



Water evaporated from and at 212 cleg, perlb. of combustible, 11.06 Ibs. 



In view of the high temperature of the gases shown in this 

 test, an evaporation of 11.06 pounds must be considered as 

 excellent work. If the heating surface under these conditions 

 had been increased so as to absorb the waste heat, as, for 

 example, by means of a suitable flue heater, the evaporative 

 result would readily have been brought up to the highest 

 standard of economy. 



Boiler No. 51. 



Kind of boiler, Vertical tubular ( rolling pin ). 



Number used, One. 



Horse-power (basis 10 sq. ft. ), . . One hundred and forty. 



Kind of coal, . / De A la ^are and Lackawanna, 



\ Anthracite, Broken. 

 Age, ... .... Ten years. 



