136 



BOILER TESTS. 



cate the true temperature. The temperature was taken in 

 each case at a point in the main Hue near the smoke arch, and 

 as the flue was common to both boilers, and both boilers were 

 in operation while the test was going on, it is probable that 

 the temperature given is in some degree an average for both 

 boilers, rather than the actual temperature for the single boiler 



tested. 



Boiler No. SO. 

 Kind of boiler, ' Horizontal return tubular. 



Number used, One. 



Horse-power (basis 12 square feet), . Fifty-three. 



Kind of coal, ...... Cumberland bituminous. 



Age, . Several years. 



Boiler No. 30 is an ordinary hori- 

 zontal tubular boiler having a special 

 arrangement of furnace for burning 

 bituminous coal. The general feat- 

 ures of the furnace and its appliances 

 are shown in the following cuts. 

 Several jets of superheated steam are 

 introduced beneath the grate, and a 

 supply of air is forced in above the 



BOILER No. 30, CROSS SEC- fuel by means of a blower. The 

 TION THROUGH FURNACE. steam is derived from the boiler, 

 and it receives its superheat from a cast iron heater placed at 

 the back end of the furnace. The quantity of steam used 

 amounted to about 8 per cent, of the whole, and this has been 

 deducted from the total evaporation to determine the net quan- 

 tities given in the table of results. 





BOILER No. 30, LONGITUDINAL SECTION. 



