Copy letter from Robert William Frederick Harrison, to the Secretaries, Manchester Literary and Philosophical Society Harrison has discovered that, with only two exceptions, the illustrations referred to in their letter were reproduced by collotype process, so no blocks are available. Text figure 12 from a paper by Ewing and Rosenhain from Philosophical Transactions of the Royal Society A 193, and plate 2, figure 1 from Humfrey's paper from Philosophical Transactions A 200. They do not loan original blocks, but he can instruct their printers to prepare electros of the two blocks, and send them on with a invoice, which should be for a very small charge. 30 April 1907