Hon. LEVI WOODBURY wrote a letter expressing regret that he could not attend the Union Meeting held at Manchester, N. H., on the 20th of November. He says that without more forbearance as to agitation of the subject of slavery, it is his solemn conviction, the Union will be placed in fearful jeopardy. He mentions as an alarming sign of the times the fact that any portion of our law-abiding community should either recommend forcible resistance to the laws, or actually participate in measures designed to overawe the constituted authorities, and defeat the execution of legal precepts issued by those authorities. This, he says, is in direct hostility to the injunctions of Washington in his Farewell Address to his grateful countrymen; and seems no less hostile and derogatory to every sound principle for sustaining public order and obedience to what the legislative agents of the people and the States have enacted. A letter from Mr. WEBSTER, written on the same occasion, also alludes to the disposition which is abroad to evade the laws, and to resist them so far as it can be done consistently with personal safety. A "still more extravagant notion," he says, "is sometimes entertained, which is, that individuals may judge of their rights and duties, under the Constitution and the laws, by some rule which, according to their idea, is above both the Constitution and the laws." Both these positions are denounced as at war with all government and with all morality. "It is time," Mr. Webster adds, "that discord and animosity should cease. It is time that a better understanding and more friendly sentiments were revived between the North and the South. And I am sure that all wise and good men will see the propriety of forbearing from renewing agitation by attempts to repeal the late measures, or any of them. I do not see that they contain unconstitutional or alarming principles, or that they forebode the infliction of wrong or injury. When real and actual evil arises, if it shall arise, the laws ought to be amended or repealed; but in the absence of imminent danger I see no reason at present for renewed controversy or contention."