Solution of a Molecular
Problem. 69 communication, and
this sulphate is, in its turn, attacked by the electrolytic oxygen. In this way the absorption of oxygen in forming the negative plate ought never to come to an end. In order to see whether this was the cas~.we allowed an experiment to continue tbr 115 hours, although the mare action was over in about 40 hours. :For the last two days of the experiment, the amount of oxygen absorbed was pretty constant, being about 9 cc. per hour, which is equivalent to 0"24 grammes of sulphate of lead formed and oxldated. The whole charge on the plate was 40 grammes of peroxide. This local action also takes place during the discharge, as is evidenced by the sulphate of lead formed on the negative plate always exceeding in amount that formed on the positive plate. Through this local action taking place during the formation of the cell, during repose, and during the discharge, the lead plate which supports the peroxide must I)e continually corroded more and more; and it is probably due to the insolubility of the sulphate formed that the destruction of this kind of secondary battery is so materially retarded in practice.