Book excerpt: The text contains no explicit reference to mathematical apparatus which has rendered eminient service in economics, especially in recent years. Some of the simpler applications of algebraic symbols and geometrical diagrams to econcomic problems are presented in an appendix. Those to whom these forms of expression tend rather to confuse than to clarify the reasoning which they embody, may thus readily spare themselves this confusion; while those to whom symbols are familiar and helpful will not be deprived of the aid to precision of conception and of argument which can hardly be afforded in equal degree by any other means.