Even the laws of political economy itself cease to guide us when they touch moral government. So long as labor is a chattel to be bought and sold, so long, like other commodities, it follows the condition of supply and demand. But if, for his misfortune, an employer considers that he stands in human relations to his workmen; if he believes rightly or wrongly, that he is responsible for them; that in return for their labor he is bound to see that their children are decently taught, and they and their families decently fed and clothed and lodged; that he ought to care for them in sickness and in old age,--then political economy will no longer direct him, and the relations between himself and his dependents will have to be arranged on quite other principles. So long as he considers only his own material profit, so long supply and demand will settle every difficulty; but the introduction of a new factor spoils the equation. And it is precisely in this debatable ground of low motives and noble emotions; in the struggle, ever failing yet ever renewed, to carry truth and justice into the administration of human society; in the establishment of states and in the overthrow of tyrannies; in the rise and fall of creeds; in the world of ideas; in the character and deeds of the great actors in the drama of life, where good and evil fight out their everlasting battle, now ranged in opposite camps, now and more often in the heart, both of them, of each living man,--that the true human interest of history resides. The progress of industries, the growth of material and mechanical civilization, are interesting; but they are not the most interesting. They have their reward in the increase of material comforts; but, unless we are mistaken about our nature, they do not highly concern us after all. Once more; not only is there in men this baffling duality of principle, but there is something else in us which still more defies scientific analysis.