The destructive avalanche of the Alps is sometimes started by the winding of a horn, and a structure so irrational as Slavery will tremble at a sound.

Slave labor, which is the mainspring and nursery of Rebel supplies, without which the Rebellion must starve, will be disorganized, while a panic spreads among slave-masters absent from their homes.

The most audacious Rebels will lose their audacity, and, instead of hurrying forward to deal parricidal blows at their country, will hurry backward to defend their own firesides.

Asserting the efficacy of this appeal, I ground myself on no visionary theories or vain hopes, but on the nature of man and authentic history.

To doubt its efficacy is to doubt that man is man, with a constant desire for liberty as for life, and it is also to doubt the unquestionable instances in our own history where this desire has been displayed by African slaves.

That a government exposed to the assaults of a merciless barbarian foe should so long reject this irresistible alliance is among questions to excite the astonishment of future ages.

We are told that the appeal will offend the Border States, and that, in this moment of trial, we must do as they tell us.

It is, of course, slave-masters who speak for the Border States; and permit me to say, such persons, continuing to swear by Slavery, are not competent witnesses.

Believing in Slavery, wedded to Slavery, they are as incompetent to testify as husband and wife are incompetent to testify for each other.

Nobody can counsel safely at this moment who adheres to Slavery, or fails to see Slavery as the origin and mainspring of the Rebellion.

Put not your trust in slave-masters,--do not hearken to their promises,--do not follow their counsels.

Such is the plain lesson of English history, of French history, of Dutch history, of every country which has dealt with this question,--ay, of Russian history at this very moment,--and such, also, is the positive caution of English…

Very well,--let the traitors fling down their arms: the sooner, the better.

But I will not dishonor officers with the commission of the United States by such imputation on their loyalty and common sense.

As officers they must know their duty too well, and as intelligent men they must know that the slaves are calculated to be their best and surest allies.

But these wise objectors forget that it is precisely in order to end the war that Slavery is to be touched, and that, when they oppose the effort, they make a “side issue” in its behalf, calculated to weaken the national arm.

God forbid that I should fail in any duty of humanity, or tenderness even; but I know no principle of war or of reason by which our Rebels should be saved from the natural consequences of their own conduct.

But this whole objection proceeds on a mistaken idea of the African slave.

Only when Napoleon, in an evil hour, sought to reënslave him, did those scenes of blood occur, which exhibit less the cruelty of the slave than the atrocious purpose of the white man.

The African is not cruel, vindictive, or harsh, but gentle, forgiving, and kind.

Nor does it appear, when the slaves left their masters, on the appeal of the British commanders, during our Revolution, that they were guilty of any excess.

It is precisely the pressure of Slavery, and not the license of Freedom, that causes overflow.

If Slavery were removed, the Africans would flow back, instead of overflowing here.

The South is their natural home, and there they will go when justice at last prevails.

Let us at all hazards prevent the extension of Slavery and the increase of the Slave Power.