Hon. John D. Crimmins of New York City, in one of his books speaks of
John Michael O’Conor. The latter was a native of New York; lieutenant in
the Third U. S. Artillery, 1812; later, regimental quartermaster; was
made captain in the spring of 1813; June 20, 1814, he was appointed
assistant adjutant-general under Gardner, on Gen. Brown’s staff, and
held the rank at the time of the battle of Chippewa, in which he
participated. He left the army in 1821. He translated, in 1824, for the
U. S. Military Academy at West Point, Guy de Vernon’s _Science of War
and Fortifications_.