By the census of 1790, Massachusetts was the fourth in population of all the States, and Maryland the sixth; but in 1860, Massachusetts was the seventh, and Maryland the nineteenth; and if each of the thirty-four States increases in the same ratio from 1860 to 1870 as from 1850 to 1860, Maryland will be only the twenty-fifth State. These facts all conclusively attest the terrible effects of slavery on Maryland, and this is only one of the dreadful sacrifices she has made in retaining the institution. As to wealth, power, and intellectual development, the loss cannot be overstated. Nor can manufactures account for the difference, as shown by the still greater increase of the agricultural Northwest. Besides, Maryland (omitting slavery) had far greater natural advantages for manufactures than Massachusetts. She had a more fertile soil, thus furnishing cheaper food to the working classes, a larger and more accessible coast, and nearly eight times the length of navigable rivers, greater hydraulic power, vast superiority in mines of coal and iron, a far more salubrious climate, cotton, the great staple of modern industry, much nearer to Maryland, her location far more central for trade with the whole Union, and Baltimore, her chief city, nearer than Boston to the great West, viz.: to the Ohio at Pittsburg and Cincinnati, the Mississippi at St. Louis, and the lakes at Cleveland, Toledo, and Chicago, by several hundred miles. Indeed, but for slavery, Maryland must have been a far greater manufacturing as well as commercial State than Massachusetts--and as to agriculture; there could be no comparison. But Massachusetts did not become a manufacturing State until after the tariff of 1824. That measure, as well as the whole protective policy, Massachusetts earnestly opposed in 1820 and 1824, and Daniel Webster, as her representative, denounced it as unconstitutional. From 1790 to 1820, Massachusetts was commercial, not manufacturing, and yet, from 1790 to 1820, Massachusetts increased in numbers 144,442, and Maryland in the same time only 87,622. Yet, from 1790 to 1820, Massachusetts, the most commercial State, was far more injured by the embargo and the late war with England than any other State. It is clear, then, that the accusation of the secession leaders that the North was built up at the expense of the South, by the tariff, can have no application to the progress of Massachusetts and Maryland, because the advance of the former over the latter preceded by more than thirty years the adoption of the protective policy, and a comparison of the relative advance of the Free and Slave States, during the same period, exhibits the same results. There is one _invariable law_, whether we compare all the Slave States with all the Free States, small States with small, large with large, old with old, new with new, retarding the progress of the slaveholding States, ever operating, and differing in degree only.