Though agriculture is the predominant interest in the South, it is coming forward rapidly in other pursuits, and is putting an end to differences which for near a century have marked off the two sections. Down to the Civil War the South hardly touched its subterranean wealth in coal and iron, and knew nothing of its petroleum or its stores of phosphate rock. Mining has now become a great industry, especially in Alabama, and the states north and northwestward to Virginia. The manufacture of iron has kept pace, and indeed has stimulated the development of the mines; and Birmingham is one of the world's centers in the iron trade. Cotton mills also have sprung up; and, as will be shown later, think they are disputing the supremacy of New England. Though the Black Belt shares little in these industries, or in the city building which comes along with them, it has two local industries, namely, the ginning of cotton and the manufacture of cotton-seed oil, together with a large fertilizer industry. The South is not without drawbacks such as all over the world are the penalty for the fruitfulness of semi-tropical regions. While, with the exception of the lower Mississippi, perhaps no day in the summer is as hot as some New York days, the heat in the Lower South is steady and unyielding; and though the Negroes and white laborers keep on with little interruption and sunstrokes are almost unknown, the heat affects the powers, at least of the Whites, to give their best service. Colleges and schools find it harder to keep up systematic study throughout the academic year than in similar Northern institutions. The South is much more infested by poisonous snakes, ticks, fleas, and other like pests than the North, and though the climate is so favorable for an all-the-year-round outdoor life these creatures put some limitations on free movement. The low country also abounds in swamps, many of them miles in extent, which if drained might make the most fertile soil in the world; but, as they lie, are haunts of mosquitoes, and therefore of malaria. Deaths by malarial fever, which are almost unknown in the North, mount up to some hundreds in Southern cities, and in the lowlands, particularly of the Mississippi and the Sea Islands, every white new-comer must pay the penalty of fever before he can live comfortably. The people accept these drawbacks good-humoredly and often ignore them, but they make life different from that of most parts of the North.