Janry 15th 1838
As I know that you take an interest in all novelties of science and art, I send you enclosed some coloured drawings of the circular crystals which I have described in the Phil. Transns for last year <1> – They are represented as they appear in my Polarising Microscope. <2> These are some of the largest kind, for they occur at least 100 times smaller in diameter and yet quite perfect in shape & colours which however of course require much higher magnifying powers to exhibit.
Yours very truly
H. F. Talbot
1. WHFT, ‘On the Optical Phenomena of certain Crystals’, Philosophical Transactions of the Royal Society of London, v. 127 part 1, 1837, pp. 25–35. Constance Talbot, née Mundy (1811–1880), WHFT’s wife made some copies of these drawings, see Doc. No: 03666.
2. WHFT’s method of placing one polarizer close to the eyepiece and another below the stage increased the contrast between the subject and the background, providing him with a better method of investigating the internal structures of crystals.