OF COAL AND RATE OF EVAPORATION. 23 
Fig. 9. 
GLELEILEL. 
Scale of feet. 
ee eee 
12, 630 6 Feet 
Bars 16 inches from the top of the arch of the bottom 
of the boiler, half inch thick, with half inch spaces. 
Plates ~°;ths of an inch thick. 
Depth of water over fire 4 feet. 
A flue carried round the boiler, with capital draught. 
A corresponding series of experiments being made with 
this boiler gave a different result from that obtained with 
the last boiler; 8.80 lbs. of water from the temperature of 
60° were evaporated by one pound of coal consumed; or, 
if we add one-sixth as equivalent to the heating of the feed 
water, the result will stand thus: 
Jn the waggon-shaped boiler 10.26 lbs. of water were 
evaporated from 212° by one pound of coal. 
In consequence of the facility with which dirt settles in 
the lower bends of this boiler it is more liable to be burned 
