Unsigned letter from Joule to the Times, says concurs with "Mr Donkin's" letter in Monday edition, but says did not omit facts about "electro-magnetism as a motive force". Explains his reasons for choosing zinc as the material sued in his experiment, and explains why batteries cannot store sufficient energy [W F Donkin's letter was published on 4 January 1858 as "Electro-magnetism as a motive power"; this is probably William Fishburn Donkin (1814-1869), astronomer.]
Former reference: Pate ref. 306.