7G Transactions of the American Institute. 



secured at the ends to cast iron tube sheets, S, S 1 . There are, also, 

 sixty-eight (68) straight tubes, of the same dimensions, secured at the 

 ends to tube sheets, S, S 2 . These tubes are all connected with each 

 other and the steam drum, D, by a series of cast iron caps or water- 

 ways, C 1 , C 2 , C 3 , and by the pipes, S P, S P 1 , these latter being flanged, 

 and secured to the tube sheets by bolts. The steam drum is of 

 wrought iron, and has a diameter of two and a half (2|-), and a length 

 of twelve (12) feet, and contains shelves, L, L, for the purpose of 

 preventing foaming. 



Description of the Lowe Boiler. — (Plate 4.) 

 This is a tubular boiler, set in brick-work. The principal claim of 

 the patentee is an improved arrangement of the flues and setting, for 

 the purpose of securing more perfect combustion. The products of 

 combustion pass from the furnace through openings into the com- 

 bustion chamber. Air is admitted to the chamber by a register the 

 amount of opening being varied, until it is judged that the best effect 

 is produced. The further course of the gases is plainly marked by 

 the arrows, through the tubes and under the boiler, passing by a drop 

 flue to the chimney. 



By this arrangement of the combustion chamber, the inventor 

 claims to effect a more perfect combustion of the gases of the fuel 

 than can be produced in any other boiler of this class. 



In the trial, two boilers, placed side by side, were tested. The 

 larger boiler was four (4) feet in diameter, fifteen (15) feet and four (4) 

 inches long, and contained forty-five (45) tubes, each three (3) inches 

 in diameter and twelve (12) feet long. The other boiler was of the 

 same length as the first, but only three and a half (3|-) feet in diameter, 

 and contained thirty-six (36) tubes, ofi the same dimensions as those 

 in the first. 



Description of the Blanchard Boiler. — (Plate 5.) 

 In this boiler a mechanical draft is employed. The air, instead of 

 being forced through the ash-pit, in the ordinary manner, is drawn, 

 much more effectively, as the inventor claims, by the action of a 

 fan-like screw, placed in the smoke-pipe above the heaters ; this fan 

 being driven by a belt from the fly-wheel of the feed-pump. By this 

 arrangement the inventor claims that he can utilize the products of 

 combustion in a most thorough manner, and also that he can employ 

 a much larger ratio of heating to grate surface than is commonly 

 possible. The boiler, as shown in the figures, is of a vertical fire 



