.Notices respecting JYew Books. 71 



BecJierches sur VElectriciU. Par G-astok Platte. 

 Paris : 1879. Pp. 271. 

 M. G-aston Plante has republished in a convenient collected 

 form the experimental researches in Electricity that have occupied 

 him for nearly twenty years. The chief points in the work are : — 

 (1) a research on the secondary currents produced by electrolytic 

 polarization ; (2) the behaviour of different metals used as elec- 

 trodes in respect of the secondary currents they yield ; (3) the 

 construction of secondary batteries of large size, and the mechanical 

 contrivances for charging them in compound circuit and discharging 

 in simple circuit ; (4) the various effects — chemical, thermic, mag- 

 netic, and mechanical — produced by the powerful discharges from 

 such batteries; (5) the analogies presented by these phenomena 

 with certain natural phenomena ; (6) the construction of an in- 

 strument called a Rheostatic Machine, for rapidly charging and dis- 

 charging a large accumulator consisting of mica plates, to be used in 

 conjunction with large secondary batteries. 



The interest of the greater part of the work is in the experi- 

 mental detail, which, however, adds little to electrical theory. 

 Some of the more important conclusions are as follows : — ■ 



The falling-off of the current observed when a saline or acidu- 

 lated solution is electrolyzed between metallic electrodes, is due to 

 various causes, of which the chief are : — (1) the insolubility of the 

 oxide formed at the positive electrode ; (2) the low conductivity of 

 the same ; (3) the resistance of the layer of saline liquid which 

 surrounds the pole if the oxide is soluble ; (4) the electromotive 

 force of the separated ions, tending to produce an inverse secondary 

 current. This current M. Plante finds to be due, in the case of 

 most metals, to the reduction of the metallic oxide formed at the 

 positive electrode, and the oxidation of the metal of the negative 

 electrode or of the hydrogen that has been liberated upon its sur- 

 face. In the case of the difficultly oxidizable metals, however, 

 such as gold or platinum, the secondary current is chiefly due to the 

 action of the hydrogen which has been more or less occluded by 

 the negative electrode, and also possibly to the gases dissolved in 

 the liquid in the neighbourhood of the two electrodes respectively. 

 In the case of the metal lead, when used as electrodes in dilute sul- 

 phuric acid, the action is very marked, the surfaces of the elec- 

 trodes becoming porous with repeated oxidation and reduction, and 

 so holding the liberated gases in loose combination to a high degree. 

 M. Plante therefore uses sheets of lead in constructing the cells 

 of his secondary batteries, which unite the double advantages of an 

 E.1T.F. as high as 2*718 volts, and an internal resistance as low as 

 0*12, or even 0*048 ohm. The inability of De la E-ive to obtain a 

 secondary current from lead was due to his use of dilute hydro- 

 chloric acid; for the chloride of lead formed at the positive electrode 

 is practically insoluble. 



Some of the phenomena of discharge studied by M. Plante are 

 of great interest, and suggestive by their analogies with natural 

 phenomena. 



