As the effort now making is extraordinary in character, so no assumption seems too extraordinary to be advanced in its support. The primal truth of the Equality of Men, proclaimed in our Declaration of Independence, is assailed, and this Great Charter of our country discredited. Sir, you and I will soon pass away, but that charter will continue to stand above impeachment or question. The Declaration of Independence was a Declaration of Rights, and the language employed, though general in character, must obviously be confined within the design and sphere of a Declaration of Rights, involving no such pitiful absurdity as was attributed to it yesterday by the Senator from Indiana [Mr. PETTIT]. Sir, who has pretended that all men are born equal in physical strength or in mental capacities, in beauty of form or health of body? Certainly not the signers of the Declaration of Independence, who could have been guilty of no such self-stultification. Diversity is the law of creation, unrestricted to race or color. But as God is no respecter of persons, and as all are equal in his sight, both Dives and Lazarus, master and slave, so are all equal in natural inborn rights; and pardon me, if I say it is a mere quibble to adduce, in argument against this vital axiom of Liberty, the physical or mental inequalities by which men are characterized, or the unhappy degradation to which, in violation of a common brotherhood, they are doomed. To deny the Declaration of Independence is to rush on the bosses of the shield of the Almighty,--which, in all respects, the supporters of this measure seem to do. To the delusive suggestion of the Senator from North Carolina [Mr. BADGER], that by overthrow of this Prohibition the number of slaves will not be increased, that there will be simply a beneficent diffusion of Slavery, and not its extension, I reply at once, that this argument, if of any value, if not mere words and nothing else, would equally justify and require the overthrow of the Prohibition of Slavery in the Free States, and, indeed, everywhere throughout the world. All the dikes, which, in different countries, from time to time, with the march of civilization, have been painfully set up against the inroads of this evil, must be removed, and every land opened anew to its destructive flood. It is clear, beyond dispute, that by the overthrow of this Prohibition Slavery will be quickened, and slaves themselves will be multiplied, while new room and verge will be secured for the gloomy operations of Slave Law, under which free labor will droop, and a vast territory be smitten with sterility. Sir, a blade of grass would not grow where the horse of Attila had trod; nor can any true prosperity spring up in the footprints of a slave.