For a merchant with many trading partners or a manufacturer with multiple product lines, the use of double-entry bookkeeping helped estimate and increase profits. By contrast, cotton planters knew where their profits were coming from: cotton.69 To earn greater profits, the key was to grow (and pick) more cotton. Thus, what is most remarkable among planters’ records is not their calculation of rates of profit—only occasionally attempted—but their analysis of labor output and the way it enabled them to grow more cotton and thus to earn higher profits.
