Letter from Edward Armand Guggenheim to D C Martin, on two papers 'The thermodynamics of non-aqueous solutions. Part I. Technique of vapour pressure measurements: the vapour pressure of benzene' by P W Allen, D H Everett and Mary Frances Penney, and 'The thermodynamics of non-aqueous solutions. Part II. The systems benzene-diphenyl, benzene-diphenylmethance and benzene-dibenzyl' by D H Everett and Mary Frances Penney Paper reference code: A177 & A178 Guggenheim writes: ' Dear Martin, Everett has sent me copies of the revised versions of the two papers by himself and Penney which I referred for the Royal Society. I have read these revised versions and have no hesitation in recommending their acceptance for publication in the Proceedings. Yours sincerely, E A Guggenheim'. Written at The University, Reading, Department of Chemistry [England]. [Both papers published in Proceedings A, 1952]. Endorsed on recto as received 27 November 1951. 26 November 1951