There was a special reason, I think, why Kearny should select a red patch for his men, although I have never seen it referred to. On the 24th of March, 1862, General McClellan issued a general order prescribing the kinds of flags that should designate corps, division, and brigade headquarters. In this he directed that the First Division flag should be a red one, six feet by five; the Second Division blue, and the Third Division a red and blue one;—both of the same dimensions as the first. As Kearny commanded the First Division, he would naturally select the same color of patch as his flag. Hence the red patch.
The contagion to wear a distinguishing badge extended widely from this simple beginning. It was the most natural thing that could happen for other divisions to be jealous of any innovation which, by comparison, should throw them into the background, for by that time the esprit de corps, the pride of organization, had begun to make itself felt. Realizing this fact, and regarding it as a manifestation that might be turned to good account, Major-General Joseph Hooker promulgated a scheme of army corps badges on the 21st of March, 1863, which was the first systematic plan submitted in this direction in the armies. Hooker took command of the Army of the Potomac Jan. 26, 1863. General Daniel Butterfield was made his chief-of-staff, and he, it is said, had much to do with designing and perfecting the first scheme of badges for the army, which appears in the following circular:—
Headquarters Army of the Potomac.
Circular.
March 21, 1863.
For the purpose of ready recognition of corps and divisions of the army, and to prevent injustice by reports of straggling and misconduct through mistake as to their organizations, the chief quartermaster will furnish, without delay, the following badges, to be worn by the officers and enlisted men of all the regiments of the various corps mentioned. They will be securely fastened upon the centre of the top of the cap. The inspecting officers will at all inspections see that these badges are worn as designated.
First Corps—a sphere: red for First Division; white for Second; blue for Third.
Second Corps—a trefoil: red for First Division; white for Second; blue for Third.
Third Corps—a lozenge: red for First Division; white for Second; blue for Third.