STP.AM noll.l'tl KXPLOSIONS. 61 



plosion takes place by tho consequent natural combustion of 



:<i-s. and then tip- tumble destruction and loss of life wo 



luenflv read of, ensues. This then illustrates in a simple 



way what happens in the case of all boiler explosions, and their 



prevention can be at once made certain and simple. As steam 



cannot lie CMinpn-ssed its force being caused by its escape or 



condensation an extra quantity or superabundance, is no more 



iry than food for an over-loaded stomach. Therefore, the 



engineer sin mid always allow the steam to escape, after the water 



!<ro>itjlit to tlii'ir lt!ijl>tt temperature. 



If by any means the steam should have been accidentally 

 shut off, then the only safe way to prevent explosion is to allow 

 tho fires to go down, so as to permit the steam to condense into 

 water before being agitated ; or else to have an escape at both 

 tho top and bottom of the boiler. 



The reason old boilers are not so apt to explode, is that the 

 " rust " at the bottom of the boiler, being largely composed of 

 vegetable matter, preserves the iron from any rapid chemical 

 action, and so prevents an accumulation of hydrogen gas suffi- 

 cient to cause an explosion. We frequently hear, however, of 

 those old boilers bursting in a quiet, peaceable way, and washing 

 out the fires, but doing no serious damage. Some of the plates 

 have tl ifii been usually found to be so completely oxydized, that 

 they were not of sufficient solidity to stand repairing. 



Should the facts here stated be widely known and acted 

 upon, we might guarantee that accidents from boiler explosions 

 will almost entirely cease. 



