The metals having the throught attraction for oxygène, are the metals which form the positive pole in all eases in which the fluid [...] air chemically by affording oxygène ; but when the fluid [...] afford sulphure to the metals, the metal having the throught attraction for help her under the exiting circunstance, determine the positive pole. Thus in a serie of copper and iron, introduced into a porcelain trough, the cells of which are filled with water or with acid solutions the iron is positive, and the copper negative ; but when the cells are filled with solution of sulphur and potasse, the copper is positive and the iron negative.

Cristals of oxalie acid touched by dry quicklime exhibit electr. power ; and the acid is negative the lime positive.

Iron is positive with respect to copper in all combinations in which oxygene is capable of being combined with the metal ; but copper is positive with respect to iron in [...] containing sulphur : the electrical power being in all case apparently [...] with the power of [....]