A good deal of excitement was created by the rescue at Boston of a person claimed and arrested as a fugitive slave, under the law of the last session. The rescue was effected by a mob, mainly of colored men, who rushed into the room where the alleged fugitive was in custody of the officers, took him therefrom, and started him on his way to Canada, where he safely arrived soon after. Intelligence of the affair was transmitted by telegraph to Washington. The President issued a proclamation, commanding obedience to the laws, and sent a message to Congress, narrating the facts, and stating that the whole power of the Government should be used to enforce the laws. The matter was referred to the Judiciary Committee in the Senate, from which two reports were made--one by Mr. BRADBURY, of Maine, stating that the President possessed all needful power, and the other from Mr. BUTLER, of South Carolina, arguing that the President could not call out either the army and navy or the militia to suppress an insurrection, without having previously issued a proclamation. No further action upon the subject was had in Congress, but a great number of arrests have been made in Boston of persons charged with participation in the rescue. Unsuccessful attempts to elect U. S. Senators have been renewed in New York, and Massachusetts. In New Jersey Commodore R. F. STOCKTON, Democrat; and in Ohio Hon. BENJAMIN F. WADE, Free Soil Whig, have been elected to the U. S. Senate. In New Hampshire two Whig and two Democratic Members of Congress have been elected. There is a Democratic majority in the Senate; in the House parties are very nearly balanced, each, at present, claiming the majority. The Free Soilers, apparently, hold the balance of power. The Governor will be chosen by the Legislature, there being no choice by the people; the regular Democratic candidate has a decided plurality over either of his opponents. In Virginia, the State election has been postponed from April to October. This has been done in consequence of the unsettled state of affairs growing out of the deliberations of the State Constitutional Convention. It is supposed that the draft of the New Constitution will be completed so that it may be submitted to the people at that time.