The recent attempt of John Brown to incite an insurrection at Harper's Ferry has created no little excitement throughout the country. Strange and desperate as the movement was, it seems to have been the natural and necessary result of the long twenty years' war, waged in the free States upon the institutions of the South, the culminating point, it is to be hoped, in a reform based on no sound principle, and which, like an epidemic, has swept over the land, fruitful only in bitter words, harsh recrimination, sectional hostility, and ending, like the last act of a tragedy, in violence and murder.The scene that has been enacted at Harper's Ferry will perhaps have the effect to open the eyes of the nation, so that they can see fully the yawning gulf, the brink of which they have at last reached, and lead them to examine the ground on which they stand; inquire what they have been doing, and what good cause can be served by a course of action which has led to such fatal results. Many lives have been sacrificed. A whole family has been ruined, and an old man has been led out to suffer the last and most terrible infliction of the law. He has been but an instrument in the hands of others, who have acted, with the exception of some political leaders, from honest convictions.The time has now come, however, for them to inquire, and for all to inquire with the utmost seriousness, if these convictions of duty have been just and commendable, or if they have been mistaken, and therefore to be condemned. Zeal without knowledge is a dangerous weapon, as all history has proved, and it is incumbent upon all, not only to do right, but to think right.