The most careless reviewer of history can hardly fail to read a rude outline of progress made by men in the rights, and consequently in the duties of war through the last twenty-five centuries. It is a happy circumstance for man--that oftentimes he is led by pure selfishness into reforms, the very same as high principle would have prompted; and in the next stage of his advance, when once habituated to an improved code of usages, he begins to find a gratification to his sensibilities, (partly luxurious sensibilities, but partly moral,) in what originally had been a mere movement of self-interest. Then comes a third stage, in which having thoroughly reconciled himself to a better order of things, and made it even necessary to his own comfort, at length he begins in his reflecting moments to perceive a moral beauty and a fitness in arrangements that had emanated from accidents of convenience, so that finally he generates a sublime pleasure of conscientiousness out of that which originally commenced in the meanest forms of mercenary convenience. A Roman lady of rank, out of mere voluptuous regard to her own comfort, revolted from the harsh clamors of eternal chastisements inflicted on her numerous slaves; she forbade them; the grateful slaves showed their love for her; gradually and unintentionally she trained her feelings, when thus liberated from a continual temptation to the sympathies with cruelty, into a demand for gentler and purer excitement. Her purpose had been one of luxury; but, by the benignity of nature still watching for ennobling opportunities, the actual result was a development given to the higher capacities of her heart. In the same way, when the brutal right (and in many circumstances the brutal duty) of inflicting death upon prisoners taken in battle, had exchanged itself for the profits of ransom or slavery, this relaxation of ferocity (though commencing in selfishness) gradually exalted itself into a habit of mildness, and some dim perception of a sanctity in human life. The very vice of avarice ministered to the purification of barbarism; and the very evil of slavery in its earliest form was applied to the mitigation of another evil--war conducted in the spirit of piratical outrage. The commercial instincts of men having worked one set of changes in war, a second set of changes was prompted by instincts derived from the arts of ornament and pomp. Splendor of arms, of banners, of equipages, of ceremonies, and the elaborate forms of intercourse with enemies through conferences, armistices, treaties of peace, &c., having tamed the savagery of war into connection with modes of intellectual grandeur, and with the endless restraints of superstition or scrupulous religion,--a permanent light of civilization began to steal over the bloody shambles of buccaneering warfare. Other modes of harmonizing influences arose more directly from the bosom of war itself. Gradually the mere practice of war, and the culture of war