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GOODWIN ELECTROLYTIC CALCIUM. 



[Nov. 4, 



3. Oxidation prevented by a covering of calcium chloride, fine 

 particles being deposited by the bursting of bubbles of chlorine 

 rapidly evolved at the anode. 



The furnace is shown in detail in Fig. 3, and all dimensions can 

 be found by reference to the scale. The bricks A support the 

 retort stand B, on which is a thick piece of asbestos C, holding by 

 the blocks D the copper coil E well up in the Acheson graphite 

 anode F and insulated from it by the asbestos G. The iron bands 

 H conduct the current from the positive cable I to the graphite 

 vessel F. The calcium grows and forms the stick J, which is started 

 by the iron cathode K connected with the negative cable L and 

 supported by the clamp M, which is drilled and tapped at N to 

 receive the screw O by which it can be raised or lowered. P is a 

 tube sliding freely on the rod Q of the retort stand, and against 

 which R is firmly screwed to make the clamp M fairly rigid without 

 interfering with its vertical motion. Fluor-spar covers the copper 

 coil and fills the space about it, while the furnace is filled with 

 calcium chloride which becomes solid at S and is kept molten at T 

 solely by the current passing through the furnace. The whole 

 apparatus was set up inside an empty wind furnace from which the 

 grate bars had been removed. In this way the escaping chlorine 

 was drawn from the room. Pure anhydrous calcium chloride was 

 used, melted in a Dixon graphite crucible and added from time to 

 time, but this was found to introduce much iron, aluminium and 

 silicon from the clay binding used in the crucible, so that finally 

 the chloride was added cold and melted by drawing an arc from 

 the iron rod K. Thus the furnace was filled sufficiently for a run. 



Fig. 5 is a diagram of the circuits. A direct current dynamo 



Figure 5. 



supplied the current to the furnace line L at about 95 volts, having 

 250 amp. fuses at C and a double pole switch at S. Regulating 



