Part I.—THE DISCHARGE AT ORDINARY ATMOSPHERIC PRESSURES. In the ‘Journal of the Chemical Society,' November, 1868, we first published an account of the chloride of silver battery, which we had devised as one of great constancy and well suited for studying the discharge in exhausted tubes ; we shortly afterwards carried the number of cells to 200, and presented a battery of 100, part of the 200, to our friend the late Mr. Gassiot, who at that time was in search of a constant battery suitable to his investigations.