Secretary Davis made many recommendations contemplating radical alterations in the military system of the Union. One of his first measures was a recommendation for the thorough revision of the army regulations. He opposed the placing of officers, at an early period of service, permanently upon the staff, and advocated a system, which, he contended, would improve the discipline and efficiency of officers, "whereby the right of command should follow rank by one certain rule." The increase of the medical corps; the introduction of camels; the introduction of the light infantry or rifle system of tactics, rifled muskets, and the Minie-ball were all measures advocated by Secretary Davis, and discussed in his official papers with a force and intelligence that make them highly valuable to the military student. He urged a thorough exploration of the Western frontier, and important changes in the arrangement of defenses against the Indians, demonstrating the inefficiency of the system of small forts for the purposes of war with the savages. To obviate, in a measure, the expense, and almost useless trouble, of locating military posts in advance of settlement, he suggested the plan of maintaining large garrisons at certain points, situated favorably for obtaining supplies and accessible by steamboat or railway. From these posts strong detachments could be supplied and equipped for service in the Indian country. His efforts were most strenuous to obtain an increase of pay to officers of the army, and pensions to the widows and orphans of officers and men, upon a basis similar to that of the navy. During the Crimean war, Secretary Davis sent a commission, of which Major-General McClellan, then a captain of cavalry, was a member, to study and report upon the science of war and the condition of European armies, as illustrated in the operations incident to that struggle. At his suggestion four new regiments--two of cavalry--were added to the army, and numerous appropriations made for the construction of new forts, improvements in small arms, and the accumulation of munitions of war. The Presidential term of Pierce expired on the 4th of March, 1857, and with it terminated the connection of Mr. Davis with the executive branch of the Government. He retired with the hearty respect of his associates, and in the enjoyment of the most confiding friendship with the late head of the Government, a feeling which is cherished by both, with unabated warmth, at this day. All parties concurred in pronouncing Mr. Davis' conduct of his department successful, able, and brilliant, and in the midst of the tide of misrepresentation, with which, during and since the war, it has been sought to overwhelm his reputation, the least candid of his accusers have been compelled to this reluctant confession.