PRINCIPLES OF COMBUSTION. 127 



of heat ; but, by the common method of constructing furnaces, 

 their collection is impossible. 



When we see smoke issuing from the flame of an ill-adjusted 

 common lamp, the heat and light are diminished in quantity. Do 

 we attempt to burn that smoke ? No ; it would be impossible. 

 Again, when we see a well-adjusted lamp burn without pro- 

 ducing any smoke, the flame is clear and white. But here, the 

 lamp has not burned its smoke ; it has burned without smoke; 

 and it remains to be shown why the same methods may not be 

 employed with regard to common furnaces, whereby they may 

 burn without smoke, and thereby give out a greater quantity of 

 heat, as in the case of the common and Argand lamp, since the 

 elements of combustion in both cases are the same. 



2. In pointing out the leading characteristics in the use of 

 coals, it is unnecessary to enter into detail of the various pro- 

 cesses of gasefaction. We will, however, give this part of our 

 subject a little attention, as the greater portion of the practicable 

 economy in the use of coal, and the management of furnaces, 

 will be found more or less connected with the combustion of the 

 gases which arise from the combustion of fuel, and as the numer- 

 ous combinations of which they are susceptible embrace the 

 whole range of temperature, from that of flame down to the 

 refrigeratory point. 



The subject of gaseous combinations, then, is undoubtedly an 

 important part of our inquiry. And those who would study the 

 economy of fuel, and the obtaining from it the greatest quantity 

 of heat, cannot altogether dispense with the part of our subject 

 which at present lies before us. Though it may not appear 

 equally interesting and important to every one, it is, neverthe- 

 less, the alpha and omega of the whole process of combustion. 

 The gardener may say, what has this to do with gardening ? 

 But we tell him, plainly, that this is an essential part of his 

 business, which will be generally admitted by intelligent men, 

 that so long as a furnace is connected with a hot-house, and 

 fuel consumed in that furnace, this must necessarily be a part 

 of his business. 



On the application of heat to bituminous coal, the first result 



