249 



trouble of lining the lire, un it IH called, ami that it kcepg alight 

 without, iv.jiiin'n^ t<i ! si im-d. i hat it , is thoroughly smokeless, 

 aiil th;ii the 'jas can If put oil or on at any moment, which in 

 leral.lc economy. 



A sen. ml and more economical arrangement as regards first coat 

 is shown in Finnic 2, Plate 5, and consists of two parts which are 

 simply added to the existing grate, viz. : the gas-pipe d with a 

 sin'/le row of holes about ,',. inch diameter, r.' inch apart along the 

 upper >id>' inclining inwanl, and an angular plate a, of cant iron, 

 with projecting ril>s b, extending from front to back on its under 

 M<1. . which serve the purpose of providing the heating surface 

 produced by the copper plate and frill-work in my first arrange- 

 ment. In using iron instead of copper it is necessary however to 

 increase tin- thickness of these plates and ribs in the inverse ratio 

 of the conductivity of the two metals, or as regards the back plate, 

 In mi J to , inch, according to Sir William Thomson's most recent 

 determination. This would be a very inconvenient thickness, and 

 in - i der to reduce it the construction is altered so as to let the 

 (inducting ribs run horizontally rather than vertically. 



An inclined plate d fastened to the lower grate bar, directs the 

 incoming air upon the heating surfaces and provides at the same 

 time a support for the angular and ribbed plate which is simply 

 dropped into its firm position, between it and the back of the 

 grate. 



The front edge of the horizontal plate has vandyked openings c, 

 forming a narrow grating, through which the ashes produced by 

 the combustion of the coke or anthracite in the front part of the 

 grate discharge themselves down the incline towards the back 

 of the hearth, where an open ash-pan may be placed for their 

 reception. 



In adapting the arrangement to existing grates, the ordinary 

 grating may be retained to support the angular plate which has 

 in that case its lower ribs cut short, to the level of the hori- 

 zontal grate. 



But, it may be asked, are you sure that the coke and gas grate 

 you advocate will do away with fogs and smoke ? My answer is, 

 that it will certainly do away with smoke, because the products of 

 combustion passing away into the chimney are perfectly trans-i 

 parent. Mr. Aitken has, however, lately proved, in an interesting 



