It is not a little singular that, while slavery has been for nearly eighty years the one root of bitterness in our politics, the general knowledge of its history should be so superficial. Abolitionism has been so persistently represented as the disturbing element which threatened the permanence of our Union, that mere repetition has at last become conviction with that large class of minds with which a conclusion is valuable exactly in proportion as it saves mental labor. Mr. Greeley's chronological narrative is an excellent corrective of this delusion, and his tough little facts, driven firmly home, will serve to spike this parrot battery, and render it harmless for the future. A consecutive statement of such of the events in our history as bear directly on the question of slavery, separated from all secondary circumstances, shows two things clearly: first, that the doctrine that there was any national obligation to consider slaves as merely property, or to hold our tongues about slavery, is of comparatively recent origin; and, second, that there was a pretty uniform ebb of anti-slavery sentiment for nearly sixty years after the adoption of the Constitution, the young flood beginning to set strongly in again after the full meaning of the annexation of Texas began to be understood at the North, but not fairly filling up again even its own deserted channels till the Southern party succeeded in cutting the embankment of the Missouri Compromise. Then at last it became evident that the real danger to be guarded against was the abolition of Freedom, and the reaction was as violent as it was sudden.