The assembling at Chicago of a great convention of soldiers and sailors at the same time the Republican Convention met, made the latter even more enthusiastic than the convention of 1860, and the number in attendance was much larger. The Soldiers' Convention met before the Republican Convention, and amid scenes of the wildest enthusiasm, nominated Gen. Grant for the presidency, and condemned the seven Republicans--"traitors" as they were then called--who had voted against the impeachment of President Johnson. At noon, May 20th, the Republican Convention was called to order by Governor Marcus L. Ward, of New Jersey. He named Carl Schurz, of Wisconsin, as temporary Chairman. The temporary Secretaries were B. R. Cowen, of Ohio, Luther Caldwell, of New York, and Frank S. Richards, of Tennessee. Committees on Credentials, Permanent Organization, Resolutions and Rules were then appointed, each of the committees, with some few exceptions, having on it a representative from each of the States. The name of Joseph R. Hawley was reported for President of the Convention, and the names of one representative from each State as Vice-President, and also thirty-six secretaries. A delegation from the Soldiers' and Sailors' Convention now presented a resolution nominating Gen. Grant for President, and it caused great enthusiasm. Such a procedure was contrary to the rules of the Convention, but the delegates were almost unanimous in desiring the nomination to be made at once, but order was finally restored. After some debate it was decided to give representation in the Convention to the Territories, and to the States not yet reconstructed. The Convention then adjourned until the following morning at ten o'clock, at which time, on assembling, impatient attempts were again made to nominate Gen. Grant contrary to the rules, but the Convention finally quieted down and listened to speeches delivered by F. Hassaurek, John M. Palmer and John W. Forney. The platform, reported by Richard W. Thompson, of Indiana, was adopted with many cheers. REPUBLICAN PLATFORM, 1868. The National Republican Party of the United States, assembled in national convention in the City of Chicago on the 21st day of May, 1868, make the following declaration of principles: 1. We congratulate the country on the assured success of the reconstruction policy of Congress, as evinced by the adoption, in the majority of the states lately in rebellion, of Constitutions securing equal civil and political rights to all; and it is the duty of the government to sustain those institutions and to prevent the people of such states from being remitted to a state of anarchy. 2. The guaranty by Congress of equal suffrage to all loyal men at the South was demanded by every consideration of public safety, of gratitude, and of justice, and must be maintained; while the question of suffrage in all the loyal states properly belongs to the people of those states.