Scope and Contents Chiefly ms text of lectures given, as follows:'Felspars' August or September 1957;'Discussion of replacements in the albite - anorthite series', no date;'A Model for the Plagioclase Felspars' ('Substance of [Montreal and] Cardiff paper, verbatim but with slight amplifications - 7.4.57.'), together with related letter from John Kempster, 10 July 1954, enclosing typescript of his 'Cardiff paper' [Institute of Physics Spring Conference, April 1957, Cardiff];H D Megaw and R E...