The ratio of increase of population, especially in this country, is one of the surest tests of public prosperity. Let us then again listen to the impartial testimony of the late census. From this we learn that the increase of population in the free States from 1830 to 1840, was at the rate of 38 per cent., while the increase of the free population in the slave States was only 23 per cent. Why this difference of 15 in the two ratios? No other cause can be assigned than slavery, which drives from your borders many of the virtuous and enterprising, and at the same time deters emigrants from other States and from foreign countries from settling among you.

The influence of slavery on population is strikingly illustrated by a comparison between Kentucky and Ohio. These two States are of nearly equal areas, Kentucky however having about 3000 square miles more than the other. [3] They are separated only by a river, and are both remarkable for the fertility of their soil; but one has, from the beginning, been cursed with slavery, and the other blessed with freedom. Now mark their respective careers.

In 1792, Kentucky was erected into a State, and Ohio in 1802.

The representation of the two States in Congress, has been as follows:

The value of land, other things being equal, is in proportion to the density of the population. Now the population of Ohio is 38.8 to a square mile, while the free population of Kentucky is but 14.2 to a square mile—and probably the price of land in the two States is much in the same proportion. You are told, much of the wealth is invested in negroes—yet it obviously is a wealth that impoverishes; and no stronger evidence of the truth of this assertion is needed, than the comparative price of land in the free and slave States. The two principal cities of Kentucky and Ohio are Louisville and Cincinnati; the former with a population of 21,210, the latter with a population of 46,338. Why this difference? The question is answered by the Louisville Journal. The editor, speaking of the two rival cities, remarks, "The most potent cause of the more rapid advancement of Cincinnati than Louisville is the absence of slavery. The same influences which made Ohio the young giant of the West, and is advancing Indiana to a grade higher than Kentucky, have operated in the Queen City. They have no dead weight to carry, and consequently have the advantage in the race."

In 1840, Mr. C. M. Clay, a member of the Kentucky Legislature, published a pamphlet against the repeal of the law prohibiting the importation of slaves from the other States. We extract the following:

"The world is teeming with improved machinery, the combined development of science and art. To us it is all lost; we are comparatively living in centuries that are gone; we cannot make it, we cannot use it when made. Ohio is many years younger, and possessed of fewer advantages than our State. Cincinnati has manufactories to sustain her; last year she put up one thousand houses. Louisville, with superior natural advantages, as all the world knows, wrote 'to rent,' upon many of her houses. Ohio is a free State, Kentucky a slave State."

Mr. Thomas F. Marshall, of Kentucky, in a pamphlet published the same year, and on the same subject, draws the following comparison between Virginia and New York:

"In 1790, Virginia, with 70,000 square miles of territory, contained a population of 749,308. New York, upon a surface of 45,658 square miles, contained a population of 344,120. This statement exhibits in favor of Virginia a difference of 24,242 square miles of territory, and 408,188 in population, which is the double of New York, and 68,600 more. In 1830, after a race of forty years, Virginia is found to contain 1,211,405 souls, and New York 1,918,608, which exhibits a difference in favor of New York of 607,203. The increase on the part of Virginia will be perceived to be 463,187, starting from a basis more than double as large as that of New York. The increase of New York, upon a basis of 340,120, has been 1,578,391 human beings. Virginia has increased in a ratio of 61 per cent., and New York in that of 566 per cent.

"The total amount of property in Virginia under the assessment of 1838, was $211,930,508. The aggregate value of real and personal property in New York, in 1839, was $654,000,000, exhibiting an excess in New York over Virginia of capital of $442,069,492.

"Statesmen may differ about policy, or the means to be employed in the promotion of the public good, but surely they ought to be agreed as to what prosperity means. I think there can be no dispute that New York is a greater, richer, a more prosperous and powerful State than Virginia. What has occasioned the difference?... There is but one explanation of the facts I have shown. The clog that has stayed the march of her people, the incubus that has weighed down her enterprise, strangled her commerce, kept sealed her exhaustless fountains of mineral wealth, and paralyzed her arts, manufactures and improvement, is NEGRO SLAVERY."

These statements were made before the results of the last census were known. By the census of 1840, it appears that in the ten preceding years,

Now let it be recollected that Maryland is nearly double the size of Massachusetts. In the last there are 98.8 free inhabitants to the square mile; in the former only 27.2.

If we turn to the new States, we find that slavery and freedom have the same influence on population as in the old. Take, for instance, Michigan and Arkansas. They came into the Union about the same time—

The ratio of increase of white inhabitants, for the last ten years, has been in Arkansas as 200 per cent; in Michigan, 574 per cent. In both instances the increase has been chiefly owing to immigration; but the ratio shows the influence of slavery in retarding immigration. Compare also Alabama and Illinois—

We surely need not detain you with farther details on this head, to convince you what an enormous sacrifice of happiness and prosperity you are offering on the altar of slavery. But of the character and extent of this sacrifice you have as yet had only a partial glimpse. Let us proceed to examine