With the extensive development of various industries in the colonies, slavery soon left the North and was used exclusively in the South. There are several reasons for this shift. In the first place, the colonies of the North were settled by people from the lower and middle classes, who had been accustomed to working for themselves and who thus had no use for slaves, while the South was settled largely by adventurers, who had never worked and who looked upon labor as dishonorable. In the second place, the North had a temperate climate in which any man could safely work, while the heat of the South was so intense that a white man endangered his life by working in it, whereas the Negro was protected by facility of acclimation. Another cause was the difference in soil. The soil of the South was favorable to the growth of cotton, tobacco, rice, and sugar, the cultivation of which crops required large forces of organized and concentrated labor, which the slaves supplied. On the other hand, the soil of the North favored the raising of cereals, which required neither organized nor concentrated labor; for one man working alone was able to produce more than one man working in a group: and thus slave labor was of little or no advantage to the North. Then, too, its soil, lacking the fertility of that of the South, required considerable fertilizing, which slave labor did not have the intelligence to learn. Thus in 1750 the slaves included three per cent of the population of the New England colonies, nine per cent of the middle colonies, and twenty-five per cent of those south of the Potomac River.[1] By the end of the eighteenth century every State north of Maryland, with the exception of New Jersey, had provided for the immediate or gradual abolition of slavery, while the rise of the cotton industry, quickened by the invention of the cotton gin in 1793, had bound the institution on the South. In order to understand the institutions of the South, it is first necessary to know something about the dominating class of people. The planters, numbering in 1860 about 384,750 and owning 2,308,518 slaves,[2] were first in the social scale and controlled affairs. "They included an aristocracy or gentry reflecting distinctions of colonial government, and expanding under influences that prevented an amalgamation of widely separated elements."[3]