446 Mr. A. Tribe on an Electrochemical Method of 



Another wife of a sou-iu-law of a person cannot be the daughter of the 



person. 

 A step-child of a sister of a woman cannot he the child of the woman. 

 A child of a sister of a step-mother of a person cannot be the person. 

 A sister of a wife of a husband of a woman cannot be the woman. 

 A parent of another wife of a son-in-law of a person cannot be the 



person. 

 A wife of a husband of a sister of a woman cannot be the woman. 

 A child of a husband of a sister of the mother of a person cannot be 



the person. 



LIX. On an Electrochemical Method of Investigating the Field 

 of Electrolytic Action. By Alfred Tribe*. 



THE electrochemical method of investigating the field of 

 electrolytic action has for its basis new facts, the nature 

 of which I propose to set forth in the first part of this commu- 

 nication, reserving the second part for the description and dis- 

 cussion of the results which have recently accrued from its 

 application. 



The Method. 



When a rectangular plate of metal unconnected with the 

 battery is placed lengthwise in an electrolyte undergoing elec- 

 trolysis, the plate does work identical in kind with that being 

 done by both electrodes. The electropositive ion of the elec- 

 trolyte separates and distributes itself on a portion of the plate 

 nearer the + electrode, and the electronegative ion on another 

 part of the plate nearer the — electrode. The respective 

 boundaries of these ions are sharply defined, and the interme- 

 dial space free from either ion. 



When an aqueous solution of copper sulphate is electro- 

 lyzed with silver electrodes, copper of course separates on the 

 — electrode; but more or less of the dark-grey or black silver 

 peroxide forms on the + electrode, yj -§ of a weber in one 

 minute produces, in fact, a sensible separation of copper and 

 a sensible formation of silver peroxide on a silver plate 

 34 millim. x 7 millim. 



It follows, therefore, that a silver plate placed in a solu- 

 tion of copper sulphate, under the conditions named in the 

 first paragraph, should have copper deposited on that part 

 which may be supposed to receive — electrification, and silver 

 peroxide on that which receives the positive. Such is the case. 



The registration of any set of electrifications in this way by 

 the ions of electrolytes need take only a few minutes, the mini- 

 mum time being determined by the dimensions of the ana- 

 lyzer f, strength of electrolyte, and available current. 



* Communicated by the Author, haying been read at the Meeting of 

 the French Association, Algiers, April 1881. 



t The rectangular silver plate is named, for convenience, the analyzing 

 plate, or, in brief, the analyzer. 



