692 Transa ctions of the American Institute. 



York harbor — is no exception. "We have so strong a conviction that 

 there is a cause for these tremendous disasters not explained in 

 any investigation we have seen, and also a remedy for their preven- 

 tion, that we have long felt it to be a matter of duty to give the public 

 the benefit of our suggestions. These may, at least, lead others to 

 pursue the same line of inquiry with more perspicacity and better 

 success. In this spirit we proceed : si quid novisti rectius istis, can 

 didus imperti. (Hor.) If you know anything preferable to the max- 

 ims laid down, candidly impart your knowledge. 



The explosions of steam boilers may be divided into two classes, 

 distinguished by the degrees of the violence or force which produces 

 them. In one the boiler is slightly, if at all, removed from its place ; 

 the shell has been opened ; some seam has given way ; the rivets 

 loosened or broken ; the end blown out, and the flues or boiler case 

 collapsed — the steam having escaped through the opening, and the 

 force having evidently, in the moment' of escape, operated in one 

 direction. These effects are such as would naturally follow in the 

 excessive pressure of the steam causing a breach of the boiler. In 

 the other class are those tremendous explosions in which the force 

 appears to have been exerted in all directions, though the greatest 

 violence may generally be traced in some particular direction ; the 

 boiler is totally ruined ; often broken apart ; sometimes into many 

 parts, scattered all around ; very heavy portions carried to a great dis- 

 tance ; large and strong buildings leveled with the ground, which is 

 covered, to a great extent, with the ruins. The destructive agency in 

 these instances is prodigious and astounding. Nothing in nature 

 approaches it in violence, if we except the earthquake and tornado ; 

 while, in the suddenness and celerity of its irresistible power, it is 

 only equaled by the thunderbolt. It is to this class we propose to 

 confine our attention. 



In the production of steam, the ostensible agents are fire, water 

 and air. To secure its available power, it is necessary to confine it 

 in some vessel of sufficient strength to keep it under the control of 

 the operator. The steam boiler intended for such a purpose must be 

 so constructed as to restrain the pressure caused by the expansion of 

 steam, while portions of it are let off in the required quantities. 

 Thus constructed, and its soundness and strength ascertained by com- 

 petent tests, it is placed in its position, and connected with the appa- 

 ratus and appliances for generating the steam. As long as the boiler 

 is sound and strong, and the pressure not allowed to exceed its 

 strength, it must be safe from fracture, and as these conditions are 



