1862.] on Gas-Furnaces^ Sfv. 537 



combined with the use of his heat regenerator, to the ignition of all 

 kinds of great furnaces. Gas has been used to supply heat, even upon 

 a very large scale, in some of the iron blast furnaces, and heat which 

 has done work once has been carried back in part to the place from 

 whence it came to repeat its service ; but Mr. Siemens has combined 

 these two points, and successfully applied them in a great variety of 

 cases — as the potter's kiln — the enameller*s furnace— the zinc-distilling 

 furnace — the tube-welding furnace — the metal-melting furnace — the 

 iron-puddling furnace — and the glass furnace, either for covered or open 

 pots — so as to obtain the highest heat required over any extent of space, 

 with great facility of management, and with great economy (one half) 

 of fuel. The glass furnace described had an area of 28 feet long and 

 14 feet wide, and contained eight open pots each holding nearly two 

 tons of material. 



The gaseous fuel is obtained by the mutual action of coal, air, and 

 water at a moderate red heat. A brick chamber, perhaps 6 feet by 12 

 and about 10 feet high, has one of its end walls converted into a fire 

 grate, i.e. about halfway down it is a solid plate, and for the rest of 

 the distance consists of strong horizontal plate bars where air enters ; 

 the whole being at an inclination such as that which the side of a heap 

 of coals would naturally take. Coals are poured, through openings 

 above, upon this combination of wall and grate, and being fued at the 

 under-surface, they burn at the place where the air enters ; but as the 

 layer of coal is from 2 to 3 feet thick, various operations go on in those 

 parts of the fuel which cannot burn for want of air. Thus the upper 

 and cooler part of the coal produces a larger body of hydro-carbons ; 

 the cinders or coke which are not volatilized, approach, in descending, 

 towards the grate; that part which is nearest the grate burns with the 

 entering air into carbonic acid, and the heat evolved ignites the mass 

 above it; the carbonic acid, passing slowly through the ignited carbon, 

 becomes converted into carbonic oxide, and mingles in the upper part 

 of the chamber (or gas-producer) with the former hydro-carbons. The 

 water, which is purposely introduced at the bottom of the arrangement, 

 is first vaporized by the heat, and then decomposed by the ignited fuel 

 and rearranged as hydrogen and carbonic oxide ; and only the ashes of 

 the coal are removed as solid matter from the chamber at the bottom of 

 the fire-bars. 



These mixed gases form the gaseous fuel. The nitrogen whicii 

 entered with the air at the grate is mingled with them, constituting 

 about a third of the whole volume. The gas rises up a large vertical 

 tube for 12 or 15 feet, after which it proceeds horizontally for any re- 

 quired distance, and then descends to the heat-regenerator, through 

 which it passes before it enters the furnaces. A regenerator is a 

 chamber packed with fire-bricks, separated so as to allow of the free 

 passage of air or gas between them. There are four placed under a 

 furnace. The gas ascends through one of these chambers, whilst air 

 ascends through the neighbouring chamber, and both are conducteti 

 through passage outlets at one end of the furnace, wherfe mingling they 

 Vol. hi. (No. 36.) 2 o 



