ABSTRACT
This chapter shows that it is Alfred Marshall's rather than W. R. Sorley's position which is quoted by various authors. It considers Marshall's analysis of mining and discusses his attitude to the idea of increasing return on the extensive margin in agriculture. Marshall's treatment of mines is more classical than neoclassical in emphasis and this is illustrated by the distinction which he makes between mines and agriculture. Eclectic though Marshall's treatment may be, it does not take up the idea of the need for the individual mine owner to determine an optimum time profile of production. In the Principles, Marshall repeats the limited treatment contained in the Economics of Industry and adds significant new material. Marshall's discussion of increasing return on the extensive margin is detailed and comprehensive involving discussion of a great number of contributing factors in a wide range of agricultural pursuits.
