The Slavery question was not the only one which developed into a chronic controversy between certain elements of Northern opinion and certain elements of Southern opinion. A review of the sectional struggle would be incomplete if it did not embrace a narrative of those differences on the tariff which at times led to serious disturbance, and, on one memorable occasion, to an actual threat of resistance to the authority of the government. The division upon the tariff was never so accurately defined by geographical lines as was the division upon slavery; but the aggressive elements on each side of both questions finally coalesced in the same States, North and South. Massachusetts and South Carolina marched in the vanguard of both controversies; and the States which respectively followed on the tariff issue were, in large part, the same which followed on the slavery question, on both sides of Mason and Dixon's line. Anti-slavery zeal and a tariff for protection went hand in hand in New England, while pro-slavery principles became nearly identical with free-trade in the Cotton States. If the rule had its exception, it was in localities where the strong pressure of special interest was operating, as in the case of the sugar-planter of Louisiana, who was willing to concede generous protection to the cotton-spinner of Lowell if he could thereby secure an equally strong protection, in his own field of enterprise, against the pressing competition of the island of Cuba. PROTECTION AND FREE-TRADE SECTIONAL. The general rule, after years of experimental legislation, resolved itself into protection in the one section and free-trade in the other. And this was not an unnatural distinction. Zeal against slavery was necessarily accompanied by an appreciation of the dignity of free labor; and free labor was more generously remunerated under the stimulus of protective laws. The same considerations produced a directly opposite conclusion in the South, where those interest in slave labor could not afford to build up a class of free laborers with high wages and independent opinions. The question was indeed one of the kind not infrequently occurring in the adjustment of public policies where the same cause is continually producing different and apparently contradictory effects when the field of its operation is changed.