PROCEEDINGS OF THE POLYTECHNIC ASSOCIATION. 869 



to those circumstauces which, in ordinary boilers, are thought to 

 result in great injury to the boiler." 



The committee are impressed with the great utility of this 

 boiler, as perfectly safe and free from explosion, even when care- 

 lessly used. The committee also favorably notice the steam mak- 

 ing qualities of this boiler, as also its economy in fuel. 



A boiler of the capacity of 80 horse power, for marine purposes, 

 was also tried. In this case the sections were vertical. From 

 cold water the steam raised to thirty pounds in eighteen minutes, 

 to sixty pounds in twenly-two minutes, to one hundred pounds in 

 twenty-six minutes, and to one hundred and fifty pounds in thirty- 

 one minutes. The steam was then run down to one hundred 

 pounds, and the apparatus connected with the main engine actuated 

 the works for the remainder of the day. Pine wood was the fuel 

 employed. The sections were taken indiscriminately from the 

 prepared stock in the works. 



The sub-committee for the experiments consisted of the follow- 

 ing gentlemen: Coleman Sellers, chairman, John Agnew, John F. 

 Frazer, Henry Morton, J. C. Cresson. 



In preparing this paper I have found it diiBcult to do proper 

 justice to this important improvement, and so condense the matter 

 as not to exceed the proper limit of time for reading it when we 

 consider that the subject involves not only an inroad upon world- 

 wide experience and prejudice, but the complete overthrow of, 

 and substitution for, systems employed wherever stationary steam 

 power is used, and that too by a contrivance not only new but 

 absolutely paradoxical. 



Experience with the boiler thus far has established the follow- 

 ing features : 



Its Absolute Safety from Destructive Explosion. 



Its Economy in Fuel. 



Its Efficiency as a Steam Generator. 



Its Reliability against Corrosion and Sedimentary Scale, 



Its Convenience in Transportation. # 



Its Facility for Enlargement and Repairs. 



And if the invention l^y proloiiged use maintains the reputation 

 it has thus far acquired — and there is no known reason to doubt 

 it — I venture the prediction that the days of plate iron boilers, at 

 least for stationary uses, arc numbered. 



Mr. Harrison, in his admirable "Essay on Steam Boilers," from 



