1876.] 



Mr. A. Tribe on Electrolysis, 



311 



Experiments III. to VIII. — The object of these was to obtain some 

 quantitative measure of the relative degree of polarization of the mole- 

 cules of the electrolyte in its different parts, and also to ascertain the 

 influence of the size of the electrodes on the same. Copper sulphate 

 and silver I found to promise greater advantages than other electrolytes 

 and conductors for these purposes. 



Experiments III. and IV. — A 5-per-cent. solution of the salt was 

 therefore employed, and a glass trough 12 inches by 4 \ and about 4 inches 

 deep. Silver plate s ^ x 5 inch were fixed on twelve uprights 1 inch 

 distant, as previously described. The whole was immersed in the copper 

 solution, in the centre of and between copper electrodes 4| inches wide, 

 i. e. completely across the trough, the electrodes being J inch distant 

 from the first and last silver strips. After being connected with the 

 battery for two hours, metallic copper was distinctly visible on the ends 

 of each of the strips of silver facing the positive pole. The copper on 

 the strips in this and in another precisely similar experiment was deter- 

 mined by the cyanide of potassium and ammonia process, after removing 

 it by digestion with dilute hydrochloric acid containing a little nitric. 

 One cub. centim. of the K Cy solution was equivalent to '00309 gram 

 of copper. 



The results were as under : — • 



No. of Strip from 

 + pole. 



Cub. centim. 



of KCy used. 



No. 1. 



No. 2. 



1. 



3-0 



2-9 



2. 



2-9 



3-0 



3. 



3-1 



2-8 



4. 



2-9 



2-9 



5. 



2-7 



3-1 



6. 



3-0 



2-9 



7. 



3-1 



2-8 



8. 



3-2 



2-9 



9. 



3-0 



— 



10. 



2-7 



2-6 



11. 



3-2 



3-0 



12. 



2-8 



3-0 



Experiments V. and VI. — The 4|-inch electrodes were now replaced by 

 others h inch wide, with the following result : — ■ 



