BOILER No. 46. 171 



worked up to the capacity noted, it could not properly be 

 called a 150 horse power boiler, unless provided with a chim- 

 ney of such height that it would produce that power with con- 

 siderably less than the full draught. The low temperature of 

 the escaping gases shows that the large area of heating surface 

 served to absorb nearly the whole of the available heat of the 

 products of combustion, and the evaporation per pound of 

 combustible from and at 212 degrees, which was 11 pounds, is 

 a favorable result. 



Boiler No. 46. 



Kind of boiler, Hor. ret. tub. (double-deck). 



Number used, . Four. 



Horse power (collective, basis 15 square feet), T wo hundred and ninoty. 



Kind of coal, Cumberland. 



Age, Six years. 



Boiler No. 46 embraces a plant of four double deck hori- 

 zontal tubular boilers set in one battery of brick work. The 

 general features of the boiler and its setting are shown in the 

 cuts of Boilers No. 41 and No. 42. It is provided with a flue 

 heater, consisting of vertical cast-iron pipes, similar to that 

 used with Boiler No. 33, the location of which, with reference 

 to boilers and chimney, is shown in ground plan in the follow- 

 ing cut. This heater has about one-half as much surface as 

 the total heating surface of the boilers, 



