Figure 1 [shown here] is a vertical section of the furnace, and Fig. 2 is a diagram to illustrate the means for regulating the electro-motive force or quantity of current across the furnace.
F is the furnace containing the charge to be treated. It has an inlet-hopper at _a_, with slides AA, by which the charge can be admitted without opening communication between the interior of the furnace and the outer air.
B is a screw conveyer by which the charge is pushed forward into the furnace.
_c´c´_ are the electrodes, consisting of blocks or cylinders or the like of carbon fixed in metal socket-pieces _c c_, to which the electric-circuit wires _d_ from the dynamo D are affixed. The current, as aforesaid, may be either continuous or alternating. _c^{ 2}c^{ 2}_ are rods of metal or carbon, which are used to establish the electric circuit through the furnace, the said rods being inserted into holes in conductors _c^{ 3}_ (in contact with the socket-pieces _c_) and in the furnace, as shown.
_g_ is the outlet for the gas or vapor, _h_ the slag-tap hole, and _x_ the opening for manipulating the charge, the said openings being closed by clay or otherwise when the furnace is at work.
I use coke or other form of carbon in the charge between the electrodes _c´_, the said coke being in contact with the said electrodes, so that complete incandescence is insured.
A means for varying the electro-motive force or quantity of current across the furnace with the varying resistance of the charge is illustrated by the diagram, Fig. 2. _c´ c^{ 2}_ indicate the electrodes in the furnace, as in Fig. 1, and D is the dynamo and T its terminals. E represents the exciting-circuit. R R are resistances, and R S is the resistance-switch, which is operated to put in more or less resistance at R as the resistance of the charge in the furnace lessens or increases. This switch may be automatically operated, and a suitable arrangement for the purpose is a current-regulator such as is described in the specification of English Letters Patent No. 14,504, of September 14, 1889, granted to William Henry Douglas and Thomas Hugh Parker.]
[Illustration: Figure 11.--DIPPING OF MATCHSTICKS in France, about 1870. The frame which holds the matches so that one end protrudes at the bottom, is lowered over a pan containing molten sulfur. The sulfur-covered matches are then dropped into a phosphorous paste. See figure 12. (From FIGUIER, _Merveilles de l'industrie_, volume 3, 1874, page 575.)]