PRINCIPLES OF COMBUSTION. 133 



information; neither let him suppose he can dispense with the 

 knowledge of this branch of the subject* if he has anything to 

 do with the combustion of coal. Without it, he is at the mercy 

 of every speculative "smoke-burning" pretender; whereas, 

 with it, his mind will be at once opened to the simplicity and 

 efficiency I may^ add, to the truth and beauty, of nature's 

 processes, as regard combustion. 



There is not, indeed, a more curious or instructive part of the 

 inquiry than that respecting the conditions and proportions in 

 which the compound gases enter into union with the constituents 

 of the air; neither is there one more intimately connected with 

 the practical details of our furnaces. These introductory remarks 

 are, therefore, necessary for those who are not already familiar 

 with it. Indeed, without some information on this head, the 

 unions of the gases might appear capricious or uncertain; 

 whereas, in fact, they are regulated by the most exact laws, and 

 subject to the most unerring calculations/* 



* Mr. Parkes observes : " We are unfurnished with any definite, 

 determinate experiments regarding the proportions in which air and fuel 

 unite during combustion. We are, practically speaking, altogether ig- 

 norant of the mutual relations which subsist between the combustible and 

 the supporter of combustion^ (the fuel and the oxygen ;) and, though we 

 know that, without oxygen, we cannot elicit heat from coal, we have yet 

 to discover the most productive combinations of the two elements. 



" Here, then, remains a wide field for research and experiment, wor- 

 thy, and, indeed, requiring the labors of a profound chemist." 



These matters are now better understood, and those "most productive 

 combinations " rendered familiar and certain, by the labors of that " pro- 

 found chemist," John Dalton, who first drew the attention of the chemical 

 world to the subject of equivalent proportions, and taught us the impor- 

 tance and necessity of ascertaining those proportions in fact, of 

 " reasoning by the aid of the balance." 



Dalton's papers were first read before the Manchester Philosophical 

 Society, and published in their memoirs, in the year 1803. These vol- 

 umes are very scarce, and I have not been able, anywhere, to meet with 

 a complete copy of them. The Royal Institution, where Davy brought 

 his great discoveries to light, contains but the five volumes of the first 

 series. These volumes, or, at least, the papers of Dalton, should be re- 

 published, for the purpose of showing the correct chain of reasoning 

 by which the mind of that acute philosopher proceeded. 



