BOILER No. 64. 217 



temperature. The actual loss due to the waste heat is no 

 doubt greater than would appear from the simple indication of 

 temperature, on account of the facility with which air finds 

 entrance into the furnace in this form of boiler, especially in 

 the case under consideration, where the brick work of the 

 setting had become deteriorated. The steam heating surface 

 produced a superheating amounting to 29 degrees. The 

 boilers developed somewhat more than their rated capacity, 

 with a draught suction of only .01) inch. 



Boiler No. 64. 



Kind of boiler, Water-tube. 



Number used, One. 



Horse-power (basis 12 square feet), . Seventy. 



Kind of coal, ...... Anthracite Lehigh, chestnut. 



Age, ........ Six months. 



Boiler No. 64 is a water tube boiler, the general features 

 and the manner of setting of which are shown in longitudinal 

 section in the following cut. This boiler consists essentially 

 of a cluster of parallel tubes, connected at either end through 

 headers, with a drum above. The water tills the whole up to 

 about the middle of the drum, and the arrangement is such 

 that, in process of operation, a circulation is established 

 through the tubes, the water starting from the back end of the 

 drum, thence passing into the tubes and returning through 

 them to the front end. The products of combustion on leav- 

 ing the furnace pass around and between the tubes, taking a 

 direction at right angles to their length. Their course lies 

 successively through three compartments, into which the 

 space is divided by means of partitions. The lower half of 

 the drum is exposed to the heat, and the upper half is covered 

 with brick work. The brick side walls of the furnace in this 

 case are provided with perforated plates, through which air is 

 admitted above the fuel, the air first passing back and forth 

 through ducts in the walls. 



