THE ELECTRIC FURNACE. 



305 



and intended mainly for the reduction of iron ores or the manufacture 

 of steel, consists of a cylindrical lire-brick structure, the inner wall of 

 which is contracted to form a narrow opening at about two-thirds of 

 its depth to the hearth proper, which lies below. At the contraction 

 is introduced a circular set of electrodes of segmental form, made of 

 the usual compressed carbon mixture, and isolated from one another 

 by intervening segments or pillars of lire brick. 



The electrode segments constitute an even number, and are con- 

 nected alternately to the positive and 

 negative poles of the source of current. 

 Means of adjustment are provided 

 which allow the segments to be fed radi- 

 ally" as they wear away. A similar circle 

 of segmental electrodes surrounds the 

 central portion of the furnace proper, 

 or crucible, which is located below the 

 contraction and provided with an outlet 

 for drawing off the molten metal as ite- 

 forms. By a suitable manipulation of 

 the current and connections to the fur- ^"'- ^'-'• 



nace it is possible with this device to secure a combination of heated 

 zones or paths through the mass of material under treatment, the 

 position of which can l)e varied at will, so as to penetrate to all i^arts 

 and secure a homogeneous and uniform fusion. 



The Readman-Parker furnace for the manvifacture of phosphorus 

 was invented independently by these two gentlemen in 1S8S, and they 

 subsequently combined their ideas to form a community of interests. 

 It consists of the usual lire-])rick structure F, tig. 12, and feeding 



hopper H, the furnace being hermetically 

 sealed in order to exclude atmospheric air. 

 A discharge flue A carries oft' the gases and 

 vapors formed during the process, and the 

 interior of the chamber is contracted at its 

 lower portion, as shown, to form a hearth. 

 'C Mutiple electrodes E E are employed, 

 facing one another in two rows, passing- 

 through the side walls of the structure, 

 while smaller electrodes e <% below them, 

 which can be brought into closer prox- 

 imit}^ are employed to start the current flow. These arc subsequently 

 withdrawn, and the action, which resembles that of a resistance fur- 

 nace with a conducting ]xith formed of the material under treatment, 

 is maintained between the main electrodes E E. 



The ingot carbide furnace recently patented by l\Ir. Parker should 

 have a decided future before it. The i)rinciple of its construction is 

 represented in sectional plan in lig. IH, in which K is a cylindrical 



Fig. 13. 



