Extract of a letter from Nevill Francis Mott, on a paper 'Photoconductivity in the infra-red region of the spectrum. II. The mechanism of photoconductivity in lead telluride' by O Simpson and Gordon Brims Black Mcivor Sutherland, to D C Martin Paper reference code: A184 'With regard to Simpson & Sutherland, I concur with the opinion of the first referee that these papers should be accepted and published as one volume of the Transactions.' With blank referee form attached 1950