Our telegraphic columns to-day will be found to contain matter of all-absorbing interest. The rebel army has opened fire upon Fort Sumter, and civil war has been inaugurated by the act of the drunken minions of JEFF. DAVIS and his Slave Oligarchy.

The hour for political speculation and compromise policy has passed. Things have assumed a definite shape. Civil war is upon us, and it is now the business of the Government to pursue such a course as will most speedily and most effectually silence the traitors and reestablish the supremacy of law and order. All squeamish sentimentality should be discarded, and bloody vengeance wreaked upon the heads of the contemptible traitors who have provoked it by their dastardly impertinence and rebellious acts. No quarters should be shown to rebels, and traitors should hang.

The dispatches received during the night, considering that the telegraph office at Charleston is in the hands of the enemy, are encouraging. What may arrive this morning and afternoon, we await with impatience, but with a firm reliance on the god of battles and the loyalty of ANDERSON and his men.

Whether or not Sumter falls into the hands of the enemy, treason must be quelled. It would be looked upon as the work of a special Providence, were ANDERSON to sustain himself for any considerable time against the combined rebel forces. But if such interposition is to be had, all good men will anticipate it on the side of LIBERTY, as arrayed against Slavery.

Men who have disgraced their northern blood by sympathising with the Southern oligarchy, had better change their tune, and that speedily. None but traitors deserving the gibbet will be found sustaining the cause of the Southern rebels. Those who are not for the stars and stripes are against them. There is no middle ground. Let the people calmly and dispassionately consider the matter, and discover to what desperate extremes the success of Southern arms would lead us. The inheritance of liberty, bought by the blood of our fathers and bequeathed with blessings to their children, will have given place to tyranny, usurpation, despotism, manacles and slavery.—In the contest now progressing by the act of the Secessionists, these evils have to be guarded against. Northern men, in the eyes of the Lords of the Lash and the breeders of quadroon bondsmen, are no better than their own chattle slaves—their own flesh and blood in chains! In a community where carnal and lascivious lusts are cultivated to the exclusion of all the more ennobling passions—where virtue is a romance, Sobriety a fiction, and liberty a lie—there need be little of honorable warfare expected; and as we have to deal with chivalrous cut-throats and self-degraded guerrillas, our actions should be shaped to meet the impending necessities.

President LINCOLN is called upon by the popular voice to pursue a determined course—a course that will most speedily and most effectually silence the vile traitors who would convert the land of the free into a chattle mart and the Goddess of Liberty into an oligarchic harlot. It is too late now to consider plans of pacific policy. The rebels have opened the batteries of the Federal Government upon a loyal garrison, and for this flagrant outrage and insult there is no punishment known to the annals of warfare too summary or severe. Let the people understand that we have a Government, by at once wiping out this Southern rebellion, though it cost ten thousand patriot lives. There are twenty millions of people in the United States who are opposed to the institution of Negro Slavery, and as the aim and intention of the secession movement is to legalize and extend that institution, and eventually to re-open the African slave trade, these people will be found steady and anxious to assist the Administration in any effort to stay the march of so damnable an enterprise.

Men who tolerated slavery as a compromise necessary to the Union of the States, will not be found pandering to the base appetites of a Southern Oligarchy, and it is necessary that Cottondom be taught this truth. Where there is no Liberty there can be no Democracy, and the great Democratic party which established and has maintained the Union of these States thus far, will be found as a unit rallying around the banner handed down to a generation who are taught to reverence JEFFERSON and worship WASHINGTON as the Father of his Country. It is too late now to enquire who or what caused the war. It is, or ought to be, sufficient to know that war exists, and by the act of a band of rebels and traitors. The Government is assailed and its stability and power threatened by an unscrupulous faction. The issue is between freedom and slavery, and, thus joined, who so base a coward as dare doubt the result!