WILLIAM SIEMENS, F.R.S. 255 



licit ing gas of superior calorific power. It consists, Fig. 4, Plate 6, 

 nf a \vrought-iroii cylindrical chamber , truncated down wards, and 

 lined \viih l>rickwork. The fuel to be converted into gas is intro- 

 dii'-.-d through a hopper b, and the cinder and ashes work out 

 through the orifice at the bottom. Instead of a grating for the 

 introduction of atmospheric air a current of heated air is brought 

 in, either through the hopper or through the orifice at the bottom, 

 and is discharged into the centre of the mass of fuel ; the effect 

 is the generation of a very intense heat at that point. The fuel, 

 after its descent through the hopper, arrives gradually at this 

 region of intense heat c, and when subjected to it, parts with its 

 gaseous constituents. At the point of maximum heat the carbon 

 is consumed, producing carbonic anhydride, which, in passing 

 through the considerable thickness of fuel surrounding this por- 

 tion, takes up a second equivalent of carbon, and becomes changed 

 into carbonic oxide. Here also the earthy constituents are for 

 the most part separated in a fused or semi-fused condition, and in 

 descending gradually reach the orifice at the bottom, whence they 

 are removed from time to time. Air enters through the bottom 

 orifice to some extent, causing the entire consumption of any 

 carbonaceous matter, which may have got past the zone of greatest 

 heat ; water is also here introduced in a hollow tray d, and after 

 evaporation by the heat of the hot clinkers, passes upwards through 

 the incandescent mass, and is converted by decomposition into 

 carbonic oxide and hydrogen gas. The exit orifices e for the gases 

 are placed ah 1 round, near the circumference of the chamber, 

 ascending upwards into an annular space/, whence they are taken 

 through pipes to the furnace or other destination. 



The advantage of this modus operandi consists in the intensity 

 of the heat produced within the centre of the mass, whereby the 

 whole of the fuel is converted into combustible gases, with the 

 least amount of nitrogen. The hydrocarbons formed in the upper 

 portion of the apparatus have to descend through the hotter fuel 

 below, and in so doing, the tar and other vapours mixed up with 

 them are decomposed, and furnish combustible gases -of a perma- 

 nent character. 



The orifice at the bottom of the apparatus may be enlarged, 

 and so arranged that, instead of ashes only being produced, coke 

 may be withdrawn, and in this way a continuous coke oven may 



