ON ELECTROLYSIS. 



343 



portions of metal -were tUted out from either end of the tuhe. These samples -were 

 then assayed and it was found that no variation whatever had been produced y 

 the current. The passag-e of the current was not maintained daring the time the 

 samples were taken, and, as diffusion would probably rapidly restore the uniformity 

 of the alloy, if the current did produce any change, care was taken in subsequent 

 experiments to remedy this detect in the manipulation. 



Dr. Lodge, in a letter to me dated April 5, 1886, asked whether it was possible 

 to employ tubes one millimetre in section ? I therefore broke off the bowls of 

 two tobacco-pipes, leaving about ten millimetres of stem attached to each of the 

 bowls which were then filled with the lead-silver alloy (containing two per cent, 

 of silver) by placing them in a bath of the fused alloy and allowing the metal to 

 enter the bowls through the stems. A current from the forty-cell battery was 

 then passed for twenty minutes when both bowls were rapidly withdrawn. The 

 contents proved on assay to be identical in composition. The ends of the stems 

 while in the bath were about five millimetres apart. 



The nature of the subsequent experiments is best shown by the sections of the 

 fire-brick receptacles submitted to the Committee and by the diagram on previous 

 page. The secondary batteries used for the electric lighting of the Slint were placed 

 at my disposal by Mr. R. A. Hill, the superintendent of the Operative Department, 

 to whose assistance I am much indebted. The weight of the alloy used in the 

 experiments was about 500 grammes. 



With the appliance arranged as shown in the diagram, the momentary applica- 

 tion of twelve cells (supplied by the P^lectrical Storage Company) projected the 

 metal (a five per cent, lead-silver alloy) from the fire-brick receptacle, while ten 

 cells rapidly heated the iron terminals to redness and fused the lead ' lugs ' of the 

 cells. It was not found practicable to employ more than four cells for any experi- 

 ment which lasted more than a few minutes, and in no case did the strength of the 

 current exceed 300 amperes. 



The following experiment with a gold-lead alloy containing about two per cent, 

 of gold is given as showing the method of working : — Before melting the alloy two 

 grammes yielded on assay OO.S&Sl grm. (or 1-99 per cent.) of gold ; after the fusion 

 had taken place the samples taken gave on assay the residts shown in the following 

 table. They were withdrawn from the cavities marked M,M, on the diagram at 

 the periods indicated in the table. 



The current used was from three of the secondary cells connected in aeries. 

 ' Total difference + 0-001 15 grm 



