BOILERS 



VERY few reali/e either the important part 

 which steam plays in the maintenance 1 and 

 operation of office buildings or the vast 

 <|iiantity of energy which is daily generated by the 

 combustion of coal ;md through the peculiar prop- 

 erties of steam safelv and economically stored and 



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ntilixed as rei|iiired in the various mechanical 

 proce^e-, nccr ary for the transportation and con- 

 venience^ of thi> great commercial center. 



Since steam wa-. fir-t ntilixed as a means of storing 

 and conveying the heat energy developed by the 

 combustion of coal and other fuels, there has been a 

 gradual development and evolution of the steam 



boiler from the time of Hero until to-day. Its removal 

 from the chain of useful mechanical appliances would 

 be followed by a complete paralysis of the world's 

 present material prosperity and activity and, until 

 some other means of storing and distributing energy 

 had been developed, an almost total paralysis of 

 commerce. 



In the earlier days steam was utilized at low 

 pressures of only a few pounds above the atmosphere. 

 Finding that an increase in pressure was accompanied 

 by an increase in the amount of work that could be 

 done per pound of fuel consumed, boiler makers 

 gradually changed their designs, until to-day the 



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