CHAPTER IX. 

 GASEOUS FUELS. 



THE heat of combustion of gaseous combustibles has been 

 determined for a great many compounds, definite and pure. 

 That of the industrial gases has been determined by different 

 operators and in different ways, with more or less happy 

 results. Its determination is often one of the greatest com- 

 mercial interest, since it is used in domestic heating as well 

 as in industrial appliances, where it is necessary to obtain 

 definite, regular working. It serves also to furnish motive 

 power to gas-engines, in which the heat of combustion is not 

 without importance. Finally, it is well to know the heat 

 produced in air or water-gas apparatus, if we wish to reach 

 the best condition for their production and use. 



For heating steam-boilers gas has given good results and 

 a very high evaporative effect. It is easily regulated, and 

 thus any required heat can be produced by simply turning a 

 valve. No smoke is generated, no soot or deposit of any 

 kind produced in the flues, and no ashes to take out of the 

 ash-pit. The fireplace needs repairing but seldom, and 

 the boiler is heated evenly and regularly, there being no 

 danger of burning out in strongly heated spots, as no such 

 spots exist. 



In metallurgical furnaces, gas possesses a decided advan- 

 tage in its long, clean, easily managed, intense flame, and this 

 advantage has been long recognized. A flame of 25 feet or 

 more in length is easily produced, and it is practically uniform 

 for its whole extent. Part of the heat usually lost up the 

 chimney can be utilized to heat the air-supply, and no more is 

 supplied than just enough for perfect combustion. 



Using gas as fuel enables the metallurgist to use poor 



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