We have not space, of course, to give anything like a report of Mr. Lincoln's speech. Although entirely unpremeditated, it was in every respect, one of the ablest we have ever heard him deliver. He set out by alluding to the fact that Judge Douglas and himself fully agreed upon one point as set forth in Douglas' Columbus speech, viz: that the fathers of this Government understood its powers over the institution of slavery better than we do now; and he proceeded to show that the Democratic party had departed from the old land marks; and set up a new theory and a different policy, and at their present rate of progress, would speedily make slavery a national institution, over which even the states should exercise no control. In this the Democracy were resisted and must be resisted by the Republicans; that their position was identical, so far as the slavery question is concerned, with that occupied by the founders of the Government; and referred to the recent glorious victories achieved by the Republicans in Ohio and other States as clearly indicative that the good old doctrines of the fathers of the Republic would yet again prevail, and become the rule of action of the Government. He continued his remarks at considerable length, and made many strong points, which again and again brought down the crowd.