OF COAL AND RATE OF EVAPORATION. 33 
dirty and could not easily be cleaned. When, therefore, the 
tubes were burned out, which took place in their third year, 
I decided to remove them, and replaced the boiler in its 
original simple form as seen below, which it will be remem- 
bered gave the result of 7.1 pounds of water evaporated. 
Fig. 21. 
CoNncLUSIONS. 
The more important conclusions to which I have been 
led from the experiments above described, may be stated 
as follows : 
1. The boiler with the two internal fire-places, evaporated 
commonly called the “ breeches boiler,” worked as ¥ oat. 
herein described, will yield ...............2ceceeeeseee 6.88 lbs 
2. The “waggon-shaped boiler,’ worked as 
herein described, will yield .........00.0 05.0: eccseeees 10.26 lbs 
3. The smallest sized “plain cylindrical boiler,” 
worked as herein described, will yield ....... atk ee Fabs 
4. The large sized “plain cylindrical boiler,” 
worked as herein described, will yield............... 7.54 lbs 
5. The “Butterly boiler,’ worked as herein 
described, will yield, for one pound of coals con- 
UO ss as n) vcagadeaseer sehavengi cad bin peneee mgheu, AETEOs 9.72 lbs 
