Emory, then of the same corps, while engaged in establishing the new boundary line between Mexico and the United States. During his service in that region he located the stage and wagon-route from San Antonio to El Paso, surveyed a part of the Rio Grande Valley, and familiarized himself with the topography and resources of Northwestern Texas and the state of Chihuahua in Mexico. Later he was transferred to Florida and made surveys for a ship canal across the peninsula from the Atlantic to the Gulf of Mexico. Subsequently he had charge of the Eleventh District in the light-house service with his headquarters at Detroit. He then became Assistant Secretary, and finally on the retirement of his friend, Captain Franklin, Engineer Secretary of the Light-House Board. He had previously asked for service with the army in Mexico, but this had been denied. His service in Texas and Florida had brought him in contact with a number of officers who afterwards became distinguished in the Civil War. Among the most notable of these were Buell, Joseph E. Johnston, McClellan, Meade, Burnside and Emory. His light-house service gave him a friendly association with Commodore Shubrick and Captain (afterwards Admiral) Jenkins of the navy, General Totten of the army, Professor Bache of the Coast survey and Professor Henry of the Smithsonian Institute, and opened to him a wide acquaintance with the scientific thought of the day. While connected with the Light-House board he planned and supervised the construction of four first-class light-houses, one for Montauk Point, two for Navesink Highlands and Sandy Hook, and one for Cape Canaveral. These were all works of the highest class, fully abreast of the world's best practice at the time.

His experience in connection with the Light-House Board prepared the way for a piece of specially useful service to the country during the exciting period just prior to the outbreak of actual hostilities between the North and the South. His position gave him access to the Secretary of the Treasury, as the chief of the department to which the Light-House Board belonged. The storm then brewing showed itself in that board, made up, as it was, of Northern and Southern men, as well as elsewhere, and being intensely loyal, Smith took measures to protect and supply the principal light-houses on the southern coast. It will be remembered that Howell Cobb of Georgia was succeeded by General John A. Dix of New York as Secretary of the Treasury, and that the latter aroused the drooping hopes of the country by his celebrated order: "If any man attempts to haul down the American flag shoot him on the spot." Smith was privy to and encouraged the issuance of that order. Immediately afterwards General Dix gave him carte-blanche over the light-house service, in pursuance of which he visited all the important southern light stations, winding up at Key West. He found that place cut off from communication with Washington, and liable to fall at once under the control of the Secessionists. The Collector of Customs was a southern man and disloyal. The people of the town were in sympathy with him, and were doing all they could to overawe Captains Hunt and Brannan, who were stationed there with a small force of regular artillery. They were loyal and able officers. Both rose to distinction afterwards, but having been left without instructions they were at a loss as to their proper course till Smith arrived with the latest news from Washington. His clear and determined counsel gave them heart and encouragement, under which they made good their hold upon the fort and the island. They were reinforced in due time, which enabled the government to hold this important strategic position at the entrance to the Gulf of Mexico till the termination of the war put an end to all danger. Before returning to the north, Smith visited Havana, where he obtained valuable information for future use.

So far his work had been preparatory, and one of the most useful features of it was his tour of duty at West Point. His services in the south, and especially at Corpus Christi, had brought on a severe attack of malarial poisoning, ending in congestive chills and shattered health, followed by sick-leave and a return to the north. Before he had entirely recovered he was ordered to West Point, as principal Assistant Professor of Mathematics. This was in 1855, but his illness had so seriously affected his head as to make it impossible for him to discharge the duties of his position in a manner satisfactory to himself. As one of his pupils, I failed to discover any lack of knowledge or perspicacity on his part. To the contrary, he impressed the sections of which he had charge as a very clear-headed man with remarkable powers of mind and great aptitude as a disciplinarian and teacher. It is now known, however, that the close attention and mental exertion which his duties required of him gave him such pain as to make it imperative that he should be relieved, and this was done at his own request after a year's hard work and suffering. The injury he had received was unfortunately never entirely overcome. Throughout the whole of his subsequent life he was subject to recurrent attacks of malaria, accompanied by pain in the head with a tendency to mental depression, which disabled him entirely at times, and upon one most important occasion compelled him to leave the field, when his interests and his inclinations demanded that he should remain. I refer now especially to the time when he was assigned by General Grant to the command of the Army of the James, to succeed Major General Butler, who was at the same time ordered to return to Fortress Monroe. It will be remembered that this order was never carried into effect, but that General Smith, who was suffering from one of his attacks, took leave of absence, much to the concern of his friends, and went by the way of Fortress Monroe to New York. There was no great movement under way at the time, but before his leave of absence had expired he was notified that the order in question had been countermanded. Various explanations were given for this action, and I shall recur to it again. But it is believed by those who were interested in General Smith, and had confidence in his unusual capacity for high command, that his relief was largely, if not altogether, due to intrigue, on the part of General Butler, aided perhaps by an exaggerated estimate on the part of General Grant of that officer's political importance, which General Smith could easily have defeated had he been on the ground in actual command of the army to which he had been assigned.

But to return to his services at West Point. It was during this year that he greatly widened his knowledge of military history and the art of war. Although far from well, he led the studious life of a scientist, and in the daily companionship of the professors and of Lieutenants Silvey and Holabird, two officers of distinguished talent and learning, he obtained new and broader views of professional subjects. He had early become noted as having an investigating mind which could not be satisfied with superficial knowledge, and for a sound and conservative judgment which gave great weight to his conclusions. He was most deliberate and methodical in his habits of thought, and had an unusually tenacious grip upon the thread of his argument. His manners and movements, while free from every appearance of hurry and excitement, were habitually so well ordered that he was enabled to cover a great deal of ground in a small space of time. Always a close student of the higher branches of his profession, and belonging to an élite corps which at that time had no part in the command of troops, he became a proficient in military organization, administration and logistics, and also in strategy and grand-tactics, as taught in the text books, long before the outbreak of the war for the Union, but it is to be observed that he never claimed to have become specially skilled in minor tactics, or in the daily routine of company or regimental service. He was, however,