108 



BOILER TESTS. 



Dimensions of Boiler No. 15. 



Diameter of shell, . . 60 in. 



Length between heads and length of tubes, . . . 15 ft. 



Number of tubes 3 inches outside diameter, .... 66 



Area of heating surface, 890 sq. ft. 



Area of grate surface, . . . . . . . 24.1 sq. ft. 



Area through tubes, . 2.7 sq. 



Area through flue, 2.4 sq. 



Height of chimney, 77 ft. 



Width of air spaces and metal bars in grates, Air 3-8 in., metal 5-8 in. 



Distance of grate to shell, 23 in. 



Distance of flat bridge wall to shell, 7 in. 



Ratio of heating surface to grate surface, . . . . 37 to 1 



Ratio of grate to tube area, 10 to 1 



Results of Tests, Boiler No. 15. 



ft. 

 ft. 



The tests on Boiler No. 15, together with those made on 

 Boilers No. 13 and 14, form a group of tests, the object of 

 which was to determine the relative economy of working to 

 maximum capacity and to medium capacity, in the case of three 

 boilers of somewhat different types. All used coal from the 

 same cargo. In the case of Boiler No. 15, as in those of No. 



