46 ANNUAL OF SCIENTIFIC DISCOVERY. 



iron, and the gas generator connected with it. The heated chamber 

 is of the usual form, but instead of a fireplace there are four passages 

 (two at each end of the chamber) leading downwards into four regen- 

 erators or chambers filled with loosely piled firebricks. The lower ex- 

 tremities of these four regen'erator chambers communicate with two 

 cast-iron reversing valves. The gas arriving from the producer through 

 a pipe is directed by the valve into one regenerator or other, according 

 to the position of the valve. The gas then ascends through the one 

 "regenerator, where it takes up the heat previously deposited in the 

 brickwork, and issues into the furnace at a point where it meets with a 

 current of heated air arising from the second regenerator to effect its 

 combustion. The products of combustion pass away through the oppo- 

 site regenerator and the reversing valves into the chimney flue. The 

 last-named regenerators receive at this time the waste heat of the fur- 

 nace, becoming heated at their upper extremity to the temperature 

 nearly of the furnace itself, but remaining comparatively cool towards 

 the bottom. Every hour or half-hour the direction of the currents is 

 reversed by a change of the valve lever, the heat before deposited in 

 the one pair of regenerators is now communicated to the air and gas 

 coming in, while the waste heat replenishes the second pair of regener- 

 ators. The gas producer consists of tAvo inclined planes upon which 

 the fuel descends, being gradually deprived in heating of its gaseous 

 constituents, and finally burnt to carbonic oxide by the air entering 

 through the grate at the bottom of the inclines. Water admitted at 

 the bottom also assists in the decomposition of the ignited coke at the 

 bottom, converting the same into carbonic oxide and hydrogen gas. 

 The saving of fuel which has been effected by this arrangement 

 amounts to from forty to fifty per cent. In the application to re-heat- 

 ing and puddling furnaces, a saving of iron has been effected, owing to 

 the mildness of the gas flame, of from three to four per cent, of the en- 

 tire quantity put in ; the iron also welds more perfectly than it does in 

 the ordinary furnaces. Smoke is entirely obviated. By another ar- 

 rangement the regenerative principle has been applied also to coke 

 ovens, the result being that the separation of the coke from its gaseous 

 constituents is effected without losing the latter. In placing the coke 

 ovens, constructed on this plan, near the works where the iron is pud- 

 dled and re-heated, the latter operation may be entirely effected by the 

 gas generated in producing the coke necessary for the blast furnace in 

 producing the pig iron. The gas resulting from the regenerative coke 

 oven may be used to heat the blast and boilers connected with the 

 blast furnace. These hitter improvements are now in course of being 

 carried into effect on a large scale. The gas produced from the last- 

 named producers is of a very illuminating character, and may, it is re- 

 ported, be used for that purpose in preference to the hydrocarbon now 

 manufactured for that purpose by a much more expensive process. 



American manufacturers desirous of acquainting themselves in detail 

 with the principles of Siemans's furnace will find a descriptive paper by 

 the inventor in the Proceedings of the Society of Mechanical Engineers, 

 London. 



