P. L. Simmonds, The Commercial Products of the Vegetable Kingdom
“ What elements of crops rain water, at summer heat, will dissolve out of ten or twenty pounds of soil, in the course of three months, is a point in agricultural science which should be made the subject of numerous and rigid experiments. In this way, the capabilities of different soils and their adaptation to different crops may be tested, in connection with practical experiments in field culture, on the same kind of earth. ”
