BOILEES No. 26 and No. 27. 



133 



No. 6. These boilers are different, however, in respect to the 

 arrangement of smoke arches from those shown, being pro- 

 vided with flush fronts. One boiler in each battery has 100 

 31 inch tubes, and the other 140 3-inch tubes. The total area 

 of opening into the air ducts of each battery is 32 square 

 inches. The area of opening through the registers of the fire 

 doors amounts to 22 square inches for each battery. 



Dimensions of Boilers No. 26 and No. 27. 



Diameter of shell, each, ....... 72 in. 



Length between heads and length of tubes, ... 16 ft. 



Number of tubes 3 inches outside diameter, each,. . . 140 



Number of tubes 3 1-2 inches outside diameter, each, . . 100 



Area of heating surface, each, 3,347 sq. ft. 



Area of grate surface, each, ....... 84 sq. ft. 



Area through tubes, each, 11.52 sq. ft. 



Width of air spaces and metal bars in grates, each, . . 3-8 in. 



Distance of grate to shell, each, 27 in. 



Distance of flat bridge to shell, each, 9 in. 



Ratio of heating surface to grate surface, each, . . . 39.8 to 1 



Katio of grate to tube area, each, . . . . . 7.3 to 1 



Results of Tests. Boilers No. 26 and No. 27. (Average of two days). 



