L'amiral [Robert] Peary, explorateur [décédé le 20 février 1920] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58588

La reine de Suède [Victoria de Bade] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 58837

[Portrait de] Fridtjof Nansen, explorateur norvégien : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 59600

Amiral [Emile] Guépratte : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 60375

Fernando Iglesias [Calderón], ambassadeur du Mexique à Washington : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 60167

Belisario Porras, président de la République de Panama : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 60558

The Effect of Cobalt Upon Current Efficiency in the Electrolysis of Zinc Sulphate Solutions

The detrimental effect of the presence of cobalt upon the current efficiency, in the commercial production of zinc by electrolysis, has been recognized for some time. Most authorities differ upon the maximum amount of cobalt allowable. This is due to the fact that the presence of other impurities either increases or diminishes the detrimental effects of the cobalt. The following tests were made with the object in view of ascertaining the relation, if any, between the amount of cobalt present and the current efficiency during the electrolysis of an otherwise pure zinc sulfate solution. The results obtained from these observations indicate that there is little apparent relation between the cobalt concentration of a given solution of zinc sulfate and the current efficiency that may be obtained on the electrolysis of that solution. For certain cobalt concentrations, however, it was noted that the time factor played an important part.

El cuarto poder :

Includes index.

El cuarto poder; novela original de Sancho Polo [pseud.]

Sequel: Moneda falsa.

La gran ciencia : original /

Includes index.

La bola;

Mode of access: Internet.