162 



BOILER TESTS. 



cient to superheat the steam, although it may have acted fav- 

 orably in reducing the amount of moisture present to the low 

 figure named. 



Boiler No. 42. 



Kind of boiler, " Double-deck "hor. ret. tub. 



Number used, Three. 



Horse-power ( collective, basis 15 square feet ), Three hundred and ninety. 

 Age, ...... o , New. 



Boiler No. 42 embraces a plant of three 60-inch "double- 

 deck " boilers set in one battery of brick-work, as indicated in 

 cross section in the folloAving cut. The longitudinal section is 

 of the same general form as that shown in the cut of Boiler 

 No. 41. This boiler, like the preceding one, has a much 

 larger area of heating surface and tube area for a given size of 

 grate than the ordinary tubular boiler, and this is its character- 

 istic feature. 



BOILER No. 42, CROSS SECTION THROUGH FURNACES. 



Dimensions of Boiler No. 42. 



Diameter of lower shell, ........ f>0 



Diameter of upper shell, 34 



Length of shell and tubes, 15 



Number of tubes ( collective ) 3 inches outside diameter, . 420 



Area of water-heating surface, 5,850 



Area of steam-heating surface, ...... 300 



in. 

 in. 



ft. 



sq. ft. 

 sq. ft. 



