Early in life, Mr. Cobb was known as a Jackson or Union man, in the thick of the nullification agitation. Either from education or nature, he seems from the first to have had a repugnance for ultraism, and has therefore never agreed with that class of southern politicians usually termed Fire-eaters. In 1842, Mr. Cobb was elected to Congress, where he, in a short time, rose to a prominent position as one of the party leaders among the Democratic members. He was especially great on parliamentary questions, and was in his way a party oracle in these matters. Though he never sympathized with the disunionists of the South, he has been a consistent as well as an ardent supporter of the institution of negro slavery. His entire course in Congress showed his strong and persistent opposition to any of the movements of the friends of freedom. He voted against the right of petition on the 3d of May, 1844, and made a strong speech in favor of utter free trade. Mr. Cobb also favored the Mexican war. In 1849, he underwent a severe contest in Georgia. While in Congress he supported the famous compromise measures, which secured to him the opposition and enmity of the southern fire-eaters. The greatest contest of his life ensued. The Union Democrats put him in nomination for Governor of Georgia, and he took the stump and was elected by a tremendous majority. In 1855, he was reëlected to Congress and was soon known as a Buchanan man. He labored for Mr. Buchanan's nomination, and when he was nominated canvassed the county in favor of his election. This secured, Mr. Cobb was rewarded for his services by a seat in the Cabinet, and as he was thought to be peculiarly fitted for the Treasury Department, he was made Secretary of the Treasury. As a member of the Cabinet, Mr. Cobb used his influence in favor of the Lecompton bill and made war upon Mr. Douglas. During the winter of 1858-9 his recommendations on the tariff question were thought to indicate a change of opinion. Formerly he was in favor of free trade, and lacking that, he was in favor of the nearest possible approach to it. But in his communications to Congress as Secretary of the Treasury, Mr. Cobb admitted that the revenues of the country were not sufficient for its expenses, and he recommended a revision of the tariff to meet the emergency. It is not probable, however, under present circumstances, that he would favor any change in the tariff. As a man--socially speaking, we mean--Mr. Cobb is a favorite. Good natured and intelligent, he is surrounded by scores of friends, who like him all the better for the fact that he has been independent enough in his political career to make enemies. JOHN C. BRECKINRIDGE.