.s/A' WILLIAM SIEMENS, F.R.S. 22$ 



ami, passing up into the furnace, meet and at once ignite, pro- 

 '1 iii-ing a strong flame, which, after passing through the heating- 

 chamber, is drawn down through the second pair of regenerators 

 to the chimney-flue. The temperature attained by the ascending 

 gas and air remains nearly constant, until the uppermost courses 

 of the regenerator brickwork begin sensibly to cool ; but by this 

 time the other two regenerators are sufficiently heated, and the 

 draught is again reversed, the stream of waste gases being turned 

 down through the first pair of regenerators, re-heating them in 

 turn, and the gas and air which enter the furnace being passed up 

 the second. 



By thus reversing the direction of the draught at regular inter- 

 vals, nearly all the heat is retained in the furnace that would 

 othenvise be carried off by the products of combustion, the tem- 

 perature in the chimney-flue rarely exceeding 300 Fahr., whatever 

 may be the heat in the furnace. The proportion of heat carried 

 off in an ordinary furnace by the products of combustion is gene- 

 rally far greater than that which can be utilized, as all the heat of 

 the flame below the temperature of the work to be heated is abso- 

 lutely lost. The economy of fuel effected in the regenerative gas 

 furnace, by removing this source of loss, and making all the heat 

 of the waste gases, however low its intensity, contribute to raise 

 the temperature of the flame, amounts in average practice to fully 

 50 per cent, on the quantity used in an ordinary furnace, and the 

 saving is greater the higher the heat at which the furnace is 

 worked. In addition to this economy in the amount of fuel used, 

 a much cheaper quality may generally be burned in the gas pro- 

 ducer than could be used in a furnace working at the same heat, 

 and in which the fuel is burned directly upon the grate in the 

 ordinary way. 



When the heat of the furnace is not abstracted continually by 

 cold materials charged into it, the temperature necessarily increases 

 after each reversal, as only a very small fraction of the heat gene- 

 rated is carried off by the waste gases. The gas and air, in rising 

 through the regenerators, are heated to a temperature nearly equal 

 to that at which the flame had been passing down, and when they 

 meet and burn in the furnace the heat of combustion is added to 

 that carried up from the regenerators, and the flame is necessarily 

 lotter than before, and raises the second pair of regenerators to 



VOL. I. Q 



