Mr. MANN. Ten times as many! Ten times 300,000 is 3,000,000; and allowing six persons to each family, this would give a population of 18,000,000 directly connected with slaveholding; while the whole free population of the south, in 1840, was considerably less than five millions! Mr. MEADE, of Virginia, here interposed and said, that where the father or mother owned slaves, they were considered the joint property of the family. I think, if you include the grown and the young, there are about three millions interested in slave property. Mr. MANN resumed. My data lead me to believe that the number does not now exceed two millions; but, at the time of the adoption of the constitution, the number directly connected with slaveholding must have been less than one million. Yet this one million have already managed to acquire the broad States of Missouri, Arkansas, Louisiana, Florida, and Texas, beyond the limits of the treaty of 1783; when, at the time the “compromises of the constitution” were entered into, not one of the parties supposed that we should ever acquire territory beyond those limits. And this has been done for the benefit, (if it be a benefit,) of that one million of slaveholders, against what is now a free population of fifteen millions. And, in addition to this, it is to be considered that the non-slaveholding population of the slave states have as direct and deep an interest as any part of the country, adverse to the extension of slavery. If all our new territory be doomed to slavery, where can the non-slaveholders of the slaveholding states emigrate to? Are they not to be considered? Has one half the population of the slaveholding states rights, which are paramount, not only to the rights of the other half, but to the rights of all the free states besides? for such is the claim. No, sir. I say that, if slavery were no moral or political evil, yet, according to all principles of justice and equity, the slaveholders have already obtained their full share of territory, though all the residue of this continent were to be annexed to the Union, and we were to become, in the insane language of the day, “an ocean-bound republic.” I now proceed to consider the nature and effects of slavery, as a reason why new-born communities should be exempted from it. First, let me treat of its economical or financial, and, secondly, of its moral aspects. Though slaves are said to be property, they are the preventers, the wasters, the antagonists of property. So far from facilitating the increase of individual or national wealth, slavery retards both. It blasts worldly prosperity. Other things being equal, a free people will thrive and prosper, in a mere worldly sense, more than a people divided into masters and slaves. Were we so constituted as to care for nothing, to aspire to nothing, beyond mere temporal well being, this well being would counsel us to abolish slavery wherever it exists, and to repel its approach wherever it threatens.