In the Senate he at once took a high position. He was made Chairman of the Military Committee of the Senate, a position he has held during his entire term of senatorial services, and which he has honored. In the long and excited debates of 1849-50, and 1850-51, Mr. Davis took a prominent part, and always what is termed an ultra-sectional position. He was the champion of the extreme South, and made some of the ablest speeches of the entire slavery debate. In September, 1851, Mr. Davis was nominated by the Democrats of Mississippi, as their candidate for Governor. He at once resigned his seat in the Senate. He lost an election by a thousand votes--and retired to his plantation. Upon the nomination of Franklin Pierce to the Presidency, he took the stump for him in several of the more doubtful southern States, and with great success. His popularity before the people as a speaker was great, and his success was in due proportion. Mr. Pierce rewarded Mr. Davis for his eminent services in the campaign by the offer of the Secretaryship of War--an office which he was peculiarly qualified to fill. He was quite successful as Secretary of War, though his unfortunate quarrel with General Scott (about the merits of which we are incompetent to pronounce an opinion), damaged his popularity with a portion of his friends. When the Pierce administration went out, Mr. Davis was reëlected United States Senator, and he has latterly been looked upon as a Democratic leader in the Senate. In his personal appearance in the Senate-room, Mr. Davis has few equals. Tall, upright, stern, and with the bearing of a prince, he at once commands the admiration of the stranger so far as his personal appearance is concerned. His military manners have followed him from the camp into the Senate. We say this in no offensive sense, though it is true that the senator often unintentionally offends by the quickness, the savageness, and the irritability of his style and speech. This is not intentional, and though it now and then gives offence, it at the same time gives great force to the sentiment which the senator may be uttering at the time. He has a peculiar voice, keyed high, yet musical, and his words come flowing out like so many cannon-balls with the force of gunpowder behind them.