148 HEATING. 



so, also, by bringing different kinds of gases into a state of 

 preparation for simultaneous action. 



The complete combustion of a body depends upon the 

 chemical union of its atoms, or elementary divisions, with their 

 respective equivalents of the supporter, oxygen; and which 

 necessarily implies the bringing together, and the mixing of 

 such atoms, previous to the mixture being fired for combustion. 



It is not our purpose to enter upon the theory of atomic mix- 

 tures, or the time required to effect their combination, which 

 will be found in the numerous chemical works of the present 

 day. We will now proceed to consider the means by which air 

 may be introduced to the furnace, to effect the combustion of the 

 gases therein generated. 



In looking for a remedy for the evils arising out of the hurried 

 state of things which the interior of a furnace naturally presents, 

 and observing the means by which the gas is effectually con- 

 sumed in the Argand lamp, it seemed manifest, if the gas in the 

 furnace could be presented by means of jets to an adequate 

 quantity of air, as it is in the lamp, the result would be the 

 same, namely, a quicker and more intimate mixture and diffu- 

 sion, and consequently a more extensive and perfect combustion. 

 The difficulty of effecting a similar distribution of the gas in 

 the furnace, by means of jets, however, seems insurmountable. 

 One alternative alone remains : since the gas cannot be intro- 

 duced by jets into the body of the air, the air might be intro- 

 duced by jets into the body of the gas ; and this will be an 

 effectual remedy. 



FIG. 33 is a section of Williams' furnace for the prevention 

 of smoke. In this furnace, the fuel, as will be seen from the 

 cut, is thrown immediately upon the grate bars, and through 

 them the air finds admission to it for the purpose of consump- 

 tion. The gases pass over the bridge C ; here they meet a cur- 

 rent of air entering just beyond the bridge, which has been 

 admitted by the air-tube , below the ash-pit /, into the air- 

 chamber d, and from thence escaping through a great number 

 of small apertures in the diffusion plate above. 



The force with which the air enters through this series of 

 jets or blow-pipes enables it to penetrate into the gases, and 



