FEW problems have astonished the modern world so much as the apparent paradox of “poverty in the midst of plenty” yet, as Sir Josiah Stamp pointed out in his Norman Lockyer Lecture to the British Science Guild, delivered on November 13 and entitled “The Calculus of Plenty”, the problem is by no means new, for just a hundred years ago, Carlyle could write that “In the midst of plethoric plenty, the people perish”. As the years have gone on, the term ‘plenty’, while still covering the glaring maladjustment of things made, longed for but unused, has gradually widened in content to mean much more. In the last few years, it has become so nebulous and over-suggestive as to be, in Sir Josiah Stamp's words, almost an intellectual menace. The conception for which it stands, however, is in all conscience, he said, serious enough, though we should not be overawed or confused by it. The rigorous analytical examination to which Sir Josiah subjected the term ‘plenty’ in the course of his lecture provides an important contribution to the elucidation of the various problems involved, which only too often are lumped together to the confusion of clear thinking. Adopting a main threefold classification with various sub-heads, he classified ‘plenty’ as first that of physical or scientific potentiality; secondly, as that of unused or unmarketed production; and thirdly, that of unused capacity.