IRON 



961 



applied. It consists of storing up the heat of the burning fuel in cellular piles of fire- 

 brick, which are subsequently made to give up their heat to the blast before it enters 

 the furnace. The most successful form of this apparatus is that known as Whitwell's 

 stove which is represented in jigs. 1233-1237. It consists of a series of parallel 

 walls of fire-brick, connected by ribs and arches into a system of rectangular flues, 



1234 



c 



1235 



which are alternately heated by the combustion of the waste gas from the top of the 

 furnace, and cooled by passing a current of cold air in the reverse direction. For the 

 more perfect combustion of the gases, ventilating holes for the admission of air are 

 perforated through the walls at a and d. The arches at the top of the stove are pro- 



1236 



1237 



vided with moveable covers at E, and similar covered holes are placed at the bottom 

 of the stove at F, for the purpose of clearing out the dust which always accumulates on 

 the brick-work when the furnace is used for heating. / is the gas inlet valve ; c, the 

 chimney valve used during the heating period ; D, the eold-blast inlet valve, and A, 

 the hot-blast valve. The latter is made with a hollow -water cooled shell and seat' 

 VOL. II. 3 a 



