770 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



is not safe, alas! is known too well! Yet, can we wonder? It is 

 made without regard to the complex operations carried on within; 

 left to the narrow notions which daily routine too frequently 

 engenders. Mechanically constructed by a boiler-maker it is con- 

 sidered safe, perfect, and will pass inspection if it is only tight, 

 and able to stand a certain pressure. 



Incrustation, that greatest source of boiler destruction, is not 

 for one moment considered. Little is done, in most boilers, to 

 insure circulation of the water, so as to carry the steam, as soon 

 as made, into the steam room. Priming is scarcely considered, 

 nor how to protect the boiler against violent and sudden strains. 

 No! it is simply made tight. As to the rest, it is left to chance 

 or good luck, and yet, if the boiler explodes, and kills and maims, 

 the result is laid on some mysterious cause, beyond the control of 

 its engineer or its owner. 



When, in a boiler, we find some attention paid to the means of 

 conveying the heat into the water, we will be sure to find the 

 question of evaporation completely set aside. When a boiler 

 foams, or makes wet steam, a steam drum is placed around the 

 chimney or the heat is carried over the top of the boiler, or a 

 super-heater is used; it is true, these have been found useful and 

 beneficial; yet they are at best but remedies and afterthoughts. 

 When not wrong in themselves they show conclusively that there 

 is something seriously wrong in the boiler. 



The plainest evidence that steam boilers are built with little 

 true knowledge of the nature and production of steam, lies in the 

 fact that more than four hundred and twenty different forms of 

 boilers are made, each claiming some superiority over the others, 

 and, strange to say, with some show of reason. 



Another evidence, and one fully as lamentable, is that one of 

 the latest boilers, and one that has some very valuable features in 

 its favor, claims to be so strong that it cannot — note this — cannot 

 hurst under any practical steam pressure! Now, Avhat would we 

 think of the intelligence of an individual who, having lost a keg 

 of gunpowder by explosion, would, to prevent the recurrence of 

 such a calamity, have his powder kegs bound with strong iron 

 hoops. Is it probable that the Pacific Mail Steamship Company 

 would carry nitro-glycerine, if put up in spheres, tested to stand 

 600 pounds pressure? In both cases, the cause, it must be evident, 

 still remains the same, and the effect, we know, would be worse. 



