576 TRANSACTIONS OF THE 



found in the journal of the Frankin Institute, Vol. XVIII page 

 221, and is as follows : " That a gradual increase of pressure can 

 produce all the effects of the most violent explosions may be 

 inferred from the cases on record, attributed with probability to 

 this cause j and was proved conclusively by the direct experi- 

 ments of this committee. In these latter, cylinders of copper 

 and iron were violently torn asunder, the parts thrown from 

 their places, scattering the materials of the temporary furnaces 

 over which they were heated, and the fire, to considerable dis- 

 tances. There are also cases well made out in which a weak 

 place in a boiler has acted as a safety valve, but such fortunate 

 circumstances are not always to be looked for, and better 

 methods having been devised of effecting the same object than to 

 imitate them by the use of their plates. The idea stated to be 

 current, namely, that a boiler does not explode if duly supplied 

 with water, is wholly untenable^ and highly mischievous in its ten- 

 dency.'' 



With regard to the means of preventing the explosion of steam 

 boilers, it must be admitted by all honest and intelligent engi- 

 neers, who have had any experience in the matter, not only that 

 none of the numerous devices which have been proposed as spe- 

 cified remedies for the danger, are at all likely to accomplish the 

 purpose for which they were designed, but that the idea of ren- 

 dering a boiler safe under great pressure, by attaching any kind 

 of apparatus to the outside, or placing detective machinery within, 

 is entirely fallacious. None of the apparatus proposed, whether 

 fusible metal plates, or plugs, or flacets, or steam whistles, or 

 an indefinite increase of the number of safety-valves, or the most 

 •elaborate modifications of feeding pumps, or machinery, or even 

 acts of Congress, can add one iota to the strength of a boiler, or 

 postpone for a moment the rupture of the metal when subjected 

 by the pressure of steam to a strain which exceeds the ultimate 

 limit of its strength, and it should be borne in mind that this 

 limit, in a steam boiler, whether used or not, is daily and hourly 

 diminishing. 



The best known means for lessening the danger of explosion, 

 "which is an inevitable attendant upon the use of all boilers sub- 

 jected to a pressure of steam are, first, to secure good materials 

 and workmanshi'p in their construction, and see that they have 

 the proper forms for strength; and next, to be well assured of 

 the integrity, intelligence, practical skill, and sound judgment 

 and experience of those entrusted 'with their management. When 

 these are wanting, no boiler can be safely worked, though fur- 



