COAL: ITS COMPOSITION AND 

 COMBUSTION 1 



GENERAL DISCUSSION OF THE ELEMENTS THAT PROMOTE 

 COMBUSTION 



BY WILLIAM H. BOOTH 



IT is usual to speak of heat under various names. It is 

 thermometric, specific, or latent. By the first is meant 

 that property of heat which sets up molecular vibrations 

 in a substance, which are capable of transmission to sur- 

 rounding bodies by radiation or by contact. 



By specific heat we mean the amount of heat energy that 

 is necessary to set up a certain degree of thermometric heat 

 in a unit of mass of some body. The same addition of heat 

 to a pound of lead that has made a pound of water com- 

 fortably warm would enable the lead to burn a hole 

 through a man's hand. 



By latent heat is understood heat that has become con- 

 verted into energy of condition without thermometric 

 manifestation, as when heat added to ice at thirty-two F. 

 enables that ice to exist as a free liquid and still only to 

 affect the thermometer to thirty-two F. Here, heat repre- 

 sents mobility of the molecules. 



In a wide general sense every chemical reaction may be 

 cited as a combustion. Certainly the converse is true 

 combustion is a chemical reaction. All substances are, in 

 a broad sense, fuels. Many are difficult to ignite. Many 

 have already entered into combustion or are results of 

 chemical processes so energetic that it is difficult to estab- 

 lish any other reaction. Lime, for example, is the product 



'Abstract of paper read before the Association of Engineers-in- 

 Charge (England). From Scientific American Supplement No. 1729, 

 February, 1909. 



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