Wessells was born in Litchfield, Connecticut, Feb. 20, 1809. After he was graduated at West Point in 1833 he took part in the Second Seminole War, first as a second lieutenant of infantry and then as first lieutenant, being promoted on July 7, 1838. In Gen. Scott's Mexican campaign he was promoted captain and received the brevet of major for gallantry at Contreras and Churubusco. In the former contest Capt. Wessells, though wounded, seized the regimental flag on the death of the color sergeant and put himself at the head of his men. On his return from the war the state of Connecticut voted him a jeweled sword, which was presented to him with military ceremonies. Capt. Wessells was on the Pacific coast in 1849-54, and was in the Sioux expedition of 1855, after which he served in the Northwest till the Civil war.