the term k, which would probably be called a constant, but is not, must be determined experimentally for each material . It would not apply above a certain moisture content which would be the dividing point between combiend and the free moisture. Since there is an overlapping between thee, no exact points exists. Furthermore, the value will very owing to weather and soil conditions under which the product was grown, the variety, its treatment between harvest in the time drying is started, etc.