SSK WILLIAM SIEMENS, F.R.S. 85 



il buck along the flue below to the hot end of the second 

 Tutor, through which they made their way to the chimney. 

 For reversing the currents through the regenerators two valves 

 led, connected by a lever, one at the hot end of the 

 Mcrators near the fire, and the other at the cool end next the 

 chimney ; whereby the heated air was made to enter the fireplace 

 by the same passage as previously, and the direction of the flame 

 through the puddling chamber was not changed. By this arrange- 

 ment the regenerative furnace was assimilated as nearly as could 

 be to an ordinary puddling furnace in form and mode of working. 

 The few furnaces constructed in this manner produced a great 

 heat with little more than one-half the consumption of fuel of 

 ordinary furnaces in doing the same amount of work. A con- 

 siderable saving of iron was also effected in puddling, owing to 

 the absence of strong cutting draughts, a mild draught being 

 found sufficient to produce the necessary heat. There still re- 

 mained drawbacks however which prevented an extensive appli- 

 cation of this form of furnace : the fire required frequent attention, 

 and it was difficult to maintain a uniform volume of flame in the 

 furnace ; the reversing valve at the hot end of the regenerators 

 was moreover liable to get out of order, and the furnace was 

 costly to erect. 



The most important step in the development of the regenerative 

 furnace has been the complete separation of the fireplace or gas 

 producer from the heating chamber or furnace itself. When a 

 uniform and sufficient supply of combustible gas is ensured, it can 

 evidently be heated just like the air, by being passed through a 

 separate regenerator before reaching the furnace, whereby its 

 heating power is greatly increased. The difficulty of maintaining 

 a uniform flame in the furnace is thereby certainly removed, and 

 there is no longer any necessity for keeping the flame always in 

 the same direction through the furnace, since the gas can be 

 introduced with equal facility at each end of the heating chamber 

 in turn, and the periodical change of direction of the flame through 

 the furnace tends only to make the heat more uniform through- 

 out : whereas in the previous plan of employing solid fuel for 

 heating in the furnace, the relative position of the fireplace and 

 heating chamber being fixed and unchangeable required tne direc- 

 tion of the flame to be kept always the same, unaltered by the 



