With the close of this war and the conclusion of peace, the non-slaveholding section took on fresh industrial life and embarked then upon that career of material exploitation and development which has placed it and the wonderful achievements of its diversified industries in the front rank of rivals in the markets of the world. From this period dates the beginning of our national policy of protection of domestic industries, and the rise of a powerful monied class in politics which bore to the new industrial interests similar relations to those sustained by the slave power to Southern labor and institutions. The early policy of a tariff for revenue with incidental encouragement inaugurated by Hamilton, was now readapted to the growing needs of the new industrialism, and the growing demands of its champions. The principle of protection was made as elastic in its practical application to tariff legislation as Northern industrial interests would, from time to time, and in their stages of rapid progress, seem to require. The labor employed by the new industrialism was free white labor, each unit of which as wage earner and citizen was vitally concerned in whatever made for its safety and prosperity. The universal prevalence of the principle of popular education, and the remarkable educational function exercised upon the mental and moral faculties of the people by a right to a voice in the government, gave to this section in due time the most intelligent, energetic and productive labor in the world. Indeed, it is now well understood that modern industrialism attains its highest efficiency as a system of production in that society where popular education is best provided for, and where participation of the masses in the business of government reaches its fullest and freest expression. The freer and the more intelligent a people, all things else being equal, the more productive will be their labor over that of a rival's who may be wanting in these regards. The early and unexpected revival and expansion of slavery in the South was thus followed and met by a rapid counterexpansion of free industrialism at the North on an extraordinary scale.