[2][3] The college, and his association with it, thereafter continued for the rest of his life, except for the few years when the school was closed during the American Civil War.

[2] During the war, Soule joined the Confederate States Army, in 1862, going to the front as captain of Company A, Crescent Regiment of Louisiana Volunteers, commanded by Col. Marshall J.

On the second day of the great Battle of Shiloh, on April 7, 1862, he was wounded and captured, was sent to prison on Johnson's Island in Lake Erie, and exchanged at Vicksburg September 17, 1862.

He was then temporarily assigned to post duty and later appointed by Gen. E. Kirby Smith as chief of the Labor Bureau District of Western Louisiana.

His work on Philosophic Practical Mathematics was described in 1922 as "the most extensive of the kind ever published, and is notable for the substitution of reasoning processes for the many arbitrary rules that have encumbered most text books on arithmetic".

[2][5] On September 6, 1860, Soule married Mary Jane Reynolds of Summit, Mississippi, with whom he had nine children, of whom six survived to adulthood.