Plate, figure 56 showing electrodes attached to copper, iron, and lead soldered together by [William Thomson] Drawing of an arrangement of electrodes and blocks of copper, iron, and lead soldered together and bent. For an earlier draft see PT/55/1/27. Subject: Physics Published in Philosophical Transactions as 'The Bakerian lecture.-On the electro-dynamic qualities of metals'. Received and read by the Royal Society on 29 February 1856. [1856]