I Had some difficulty in choosing a title for this paper. I might have called it “A Plea for More Practical Mathematics”, but there would have been a doubt as to whether “more “ qualified “practical “ or “mathematics ”. And I am not very fond of the word “ practical” De Morgan's remark that the self-styled practical man could always be relied on to produce some false logic is too often true. “Practical “ is invariably used as the antithesis of “theoretical “ The boy often regards theoretical chemistry as an unneces¬sary interruption of the practical work ; he does not always regard them as complementary, like bread and butter.