“GENTLEMEN:--Your letter inviting me to be present at a mass meeting of the loyal citizens to be held at New York on the 4th instant, for the purpose of expressing gratitude to Lieutenant-General Grant for his signal services, was received yesterday. It is impossible for me to attend. I approve, nevertheless, whatever may tend to strengthen and sustain General Grant and the noble armies now under his direction. My previous high estimate of General Grant has been maintained and heightened by what has occurred in the remarkable campaign he is now conducting; while the magnitude and difficulty of the task before him do not prove less than I expected. He and his brave soldiers are now in the midst of their great trial, and I trust that at your meeting you will so shape your good words that they may turn to men and guns moving to his and their support. “Yours truly, A. LINCOLN.” On the 7th of June, the Republican National Convention met at Baltimore for the purpose of nominating candidates for the Presidency and Vice-Presidency. For some time prior to the assembling of this body, the popular voice had pronounced decidedly in favor of the renomination of Mr. Lincoln. State Legislatures, mass meetings, State Conventions, the large majority of the loyal press demanded that the man, to whose election, constitutionally effected, the rebels had refused to submit and who, during three years of the most arduous labors, had evinced his patriotism, his ability, and his integrity, should have the satisfaction of seeing the work commenced by himself as President brought to a successful completion while an incumbent of the same high office. A few, however, in the ranks of the loyal and patriotic, were not satisfied that the good work, whose consummation they so ardently and perhaps, impatiently, desired, had been pushed forward as vigorously and earnestly as it might have been under other auspices. A portion of these favored the postponement of the Convention till a later day, after the fourth of July ensuing, in the expectation that the country would be in a better condition to judge whether, indeed, Mr. Lincoln was the best man for the place. Another portion had already assembled at Chicago and put in nomination, upon a platform devoted mainly to criticisms of Mr. Lincoln’s Administration without any practical or pertinent suggestion as to the points wherein improvement was to be made, General Fremont for the Presidency and General Cochrane as Vice-President. The former had therefore resigned his commission in the army, not having been in active service for some time, and accepted the nomination conditionally that the Baltimore Convention nominated no other candidate than Mr. Lincoln.