The owners of serfs, especially, are apt to be very wasteful of their labor, because they imagine that they obtain it gratis. Tucker has made a curious calculation tending to show that when civilization reaches a certain point, the master’s self-interest leads to emancipation. In Russia, where there are seventy-five persons to the English square mile, it seemed to him that serfdom was still a good economic speculation. In western Europe, where there were one hundred and ten persons to the square mile, freedom, in all relations of master and servant, he considered more advantageous to all parties. Emancipation began in England in the fourteenth century, when that country had a population of forty to the square mile, and was completed in the seventeenth, when the population was ninety-two to the square mile.(420) Tucker concludes, that the turning point comes, when the population is relatively to the number of square miles as 66:1.(421) Such a calculation cannot, of course, be universally true. The free workman can usually command a much larger portion of the sum total of economic profits than can the slave or serf, who must be satisfied with the minimum necessary to support life.(422) Hence, free labor is more profitable to masters only when production in general is so much enhanced thereby that a greater quantity of goods falls to their share also. But this will always be the case where workmen are capable of development.(423) Section LXXII. Effect Of An Advance In Civilization On Slavery. At the same time, the same degree of servitude becomes more and more oppressive to the bondman as civilization advances. The greater his intellectual progress, the more does he feel the want of liberty, and the more keenly he experiences the degradation of his condition. The development of luxury digs a gulf between master and servant which grows wider every day. (§ 227 ff.) As commerce extends, it becomes more profitable for the master to exact excessive work from his slave. In the West Indies, it was a problem which every slaveholder solved for himself, whether, by immoderately increased production, which cost the lives of many slaves, the gain in sugar was greater than the loss occasioned by the consequent death of the negroes.(424) When, with the advance of civilization, the state guarantees to all more certain protection of their rights than they enjoyed in a less advanced stage of social improvement, the last check on masters, the fear of the vengeance of their slaves, is removed.(425) Demoralization naturally increases in the same proportion; and that of the master as well as that of his servants.(426) Section LXXIII. The Same Subject Continued.