BOILER No. 58. 



203 



Boiler No. 58. 



Kind of boiler, 



Number used, ..... 

 Horse-power ( collective, basis 12 sq. ft. ) 



Kind of coal, 



Age, 



Boiler No. 58 is a vertical 

 boiler of somewhat novel form, 

 the general features of which 

 are shown in elevation in the 

 following cut. The boiler is of 

 the fire box type, the water leg 

 of which is provided with two 

 opposite openings for the intro- 

 duction of fuel. The tubes are 

 divided into three sections ar- 

 ranged in concentric circles. 

 The first section embraces the 

 inner tubes. These carry the 

 products of combustion upward 

 from the furnace to a combus- 

 tion chamber, which is located 

 inside the boiler, below the 

 water line. The second em- 

 braces those in the next circle, 

 and through these the products 

 of combustion pass downward. 

 The third section embraces the 

 outer tubes, which carry the 

 gases upward to the space sur- 

 rounding the steam dome, 



Vertical tubular. 



Two. 



Two hundred and ten. 



Clearfleld bituminous. 



Four years. 



BOILER No. 58, VERTICAL 

 SECTION. 



whence they finally enter the chimney flue. The proportion 

 of water heating surface to grate surface, which is 35.1 to 1, 

 is nearly double that which is found in the rolling pin type of 

 boiler, and the proportion of steam heating surface to grate 

 surface is less than one-half of that found in the boiler noted. 

 The arrangement of tubes, which provides for a downward 

 current of the gases through a part of their passage, secures a 



