Shortly afterwards Smith was transferred to Grant's staff as Chief Engineer, and we messed and served together, in the closest intimacy throughout that campaign, and until I was assigned to duty in the War Department in charge of the Cavalry Bureau. I saw him frequently while I was commanding a division of cavalry and he an army corps in Grant's overland campaign against Richmond. During the latter period we were exceedingly intimate, and when we were not serving together an active correspondence was kept up between us. It is a source of pleasure and satisfaction to me that this intimacy became still closer after General Smith was appointed agent of the United States and assigned as a civil engineer to the charge of the river and harbor works on the Delaware and Maryland peninsula, with his office at Wilmington, Delaware. This long and close intimacy, extending as it did over the greater part of a lifetime, has afforded me an ample opportunity of studying his character and familiarizing myself with the facts of his military career, and with the point of view from which he considered his relations to the men and events with which he was so conspicuously connected. A man of great purity of character and great singleness of purpose, he took an intense interest in whatever his hand found to do. He felt a deep and abiding concern in all public and professional questions, and was both a tender and affectionate friend and an unrelenting enemy. He was a bold and resolute thinker who indulged in no half way measures. The bolder his plans and the more dangerous his undertakings, the more careful was he in working out the details, and the more attentive was he in supervising their execution. He left nothing to chance, but provided for every possible contingency with infinite care and yet he was a rapid worker. Methodical in his habits, untiring in his application and deliberate in his manner, he was always ready, always on time and nearly always successful. In following him through the trials and vicissitudes of his active life it will be seen that he was one of the most interesting personalities of his day. He played a bold and distinguished part in the war for the Union, quite out of proportion to the actual command which fell to his lot. Indeed, it may well be doubted if any other single officer exerted a more potential or beneficial influence than he did upon the plans and operations in which he took part. While he was austere and reserved in manners, he was most highly esteemed by all with whom he served, and received unstinted praise for his suggestions and assistance, and yet strangely enough he became involved in several notable military controversies, which so enlisted his interest and wounded his pride as to materially change his career and cause him great unhappiness, during the later years of his life.