THE 

 * LONDON, EDINBURGH and DUBLIN 



PHILOSOPHICAL MAGAZINE 



AND 



JOURNAL OF SCIENCE, 



[FOURTH SERIES.] 



FEBRUARY 1857. 



XIII. On the Electric Conducting Power of the Metals of the 

 Alkalies and Alkaline Earths. By A. Matthiessen, Ph.D.* 



[With a Plate.] 



THE electric conducting power of one of these metals, potas- 

 sium, was determined by Becquerel about thirty years agof ; 

 he found its ratio to that of silver to be 1'7 : 100, whereas ac- 

 cording to my experiments this ratio appears to be 22'6 : 100. 

 He, however, is not sufficiently explicit in the description of the 

 method he employed for one to ascertain the cause of this great 

 difference in our results. Latterly, after my experiments on the 

 alkaline metals were finished and the results already printed f, 

 M. Lamy§ published a notice on the electric conducting power 

 of potassium and sodium, wherein he only states the place in the 

 series these two metals take compared with those whose conduct- 

 ing powers are already decided ; in this respect his results agree 

 with mine. 



For these experiments I employed wires formed by pressure. 

 The press consisted of a small block of steel, the section of which 

 (Plate I. fig. 1) shows it of its natural size. In the hole, which 

 ends in a fine round opening, the metal is placed, and the steel 

 piston being fitted on, the press is fixed between two small iron 

 bars, which are then placed in a vice. Potassium, sodium and 

 lithium, on account of their strong tendency to oxidation, were 

 pressed immediately in a trough filled with rock-oil, the oil 



* Communicated by tlie Author. 



t Annales de Chimie et de Physique, vol. xxxii. p. 420. 



X Phil. Maf;. September 185G. 



§ Comptes Rendtis, vol. xliii. p. 695. 



Phil. Mag. S. 4. Vol. 13. No. 84. Feb. 1857. G 



