318 



Intelligence and Miscellaneous Articles. 



4th weaker (15-per-cent.). I immersed the one electrode in glass 1, 

 the other successively in 2, 3, 4, 5. When the second electrode 

 dipped in 3 and 5 I obtained no current, because the concentra- 

 tions of the terminal solutions were equal ; but on the immersion 

 of this electrode in glass 2, and in 4, there was always a deflection 

 produced — in the one case by the electromotive force 9, between 

 solutions of 45 and 60 per. cent., in the other by the force 13, in 

 the opposite direction, between 45- and 15-per-cent. solutions. 



I made the same experiments on a series of other salts, and thus 

 determined the 1 5 electromotive forces between the couples formed 

 by six solutions of cupric sulphate : — 





B 







D 



E 



F 



A 



10 



16 



21 



25 



27 



B 





6 



11 



15 



17 



C 







5 



9 



11 



D 









4 



6 



E 











2 



E was a solution containing, in 100 parts, 30 of crystallized salt 

 (CuS0 4 -|-5H 2 0). One hundred parts by volume of this solution 

 were mixed in E with 33|, in D with 100, in C with 300, in B with 

 700, in A with 2900 parts of water. 



By these currents, going from the diluted to the concentrated 

 solution, metal is dissolved in the diluted, and separated from the 

 concentrated solution. Only when the concentration is the same 

 in both solutions does the current cease. 



Eor the work accomplished by the current we should have to seek 

 the corresponding equivalent in the work of the force of attraction 

 between the salt and the water, which makes itself perceptible in 

 the thermal actions which can be observed on mixing different solu- 

 tions of the same salt. 



Accordingly the current observed by me must be conceived as a 

 reaction- current against the migration of the ions, as the polariza- 

 tion-current is one of reaction against the decomposition-current ; 

 for whenever any salt is electrolyzed, the solution becomes more 

 concentrated at the anode, more dilute at the cathode. My expe- 

 riments show that then arises an electromotive force which acts in 

 opposition to that of the electrolyzing battery. — MonatsbericJit der 

 Jcon. preuss. Akad. d. Wissensch. z. Berlin, Nov. 1877, pp. 674-676. 



ON THE EXTRACTION OF GALLIUM. 

 BY MM. LECOQ DE BOISBAUDRAN AND E. JUNGFLEISCH. 

 The smallness of the quantity contained in the minerals in which 

 gallium has hitherto been detected renders its preparation costly 

 and tedious. "We proposed to ourselves to pursue a process per- 

 mitting this preparation to be annexed to that of a commercial 

 product, and thence to operate on a manufacturing-scale, on con- 

 siderable masses. 



The realization of this project w T e owe to the support of M. Leon 



