The advantage of superior knowledge is not limited to the prestige of superlative scholarship, but asserts itself in the chances of every competitive pursuit, so infallibly, indeed, as to justify Diderot’s paradox that there is no need of any such thing as love of science for its own sake, since all knowledge repays its acquisition by collateral benefits. A farmer’s boy studying statute law, a lawyer collecting market reports, will sooner or later find a chance to profit by their study. The infinite interaction of human affairs connects the interests of all branches of human knowledge, and makes the humblest handicraft amenable to scientific improvement. Knowledge has never hindered the successful pursuit of any manual vocation. Fifty years ago several states of the American Union made it a penal offense to teach a slave reading and writing; and if the planter valued his laborers in proportion to their canine submissiveness, he was perhaps right that “education spoils a nigger.” It qualified his servility, and by making him a better man, made him perhaps a less available dog. But with that single exception, ignorance is a disadvantage, and knowledge an advantage, both to its possessor and his employers. In the solitudes of the Australian bush-land, Frederick Gerstäcker found a herdsman reading Aristophanes in the original. Neither the sheep nor their owners were any the worse for that incidental accomplishment of the poor shepherd, who found his study a sufficient source of pastime, while his comrades were apt to drown their ennui in bad rum. James Cook, the greatest of modern maritime discoverers, served his apprenticeship on board of a coal-barge and employed his leisure in studying works on geography and general history. The knowledge thus acquired might seem of no direct advantage, but three years after, on board of the Eagle frigate, the erudition of the brawny young sailor soon attracted the attention of two intelligent officers whose recommendations proved the stepping-stones of his successful career. Mohammed Baber Khan, the emperor of the Mogul empire, owed his triumphs to his topographical studies of a region which afterward became the battleground of his great campaigns. Mohammed the Prophet gained the confidence of his first employer by his familiarity with the commercial customs of neighboring nations. Superior knowledge compels even an unwilling recognition of its prestige. In the Middle Ages, when Moslems and Trinitarians were at daggers drawn, Christian kings sent respectful embassies to solicit the professional advice of Ibn Rushd (“Averroes”), the Moorish physician. During the progress of the life-and-death struggle of France and Great Britain, the discoveries of Sir Humphrey Davy impelled the Academie Française to send their chief prize to England. The benefits of great inventions are too international to leave room for that envy that pursues the glory of military heroes, and