Officers 
February 24, 1863 to July 10, 1865
(August 29, 1862 - February 24, 1863)

Generals Grant and McClernand forced Cooley and his officers to resign on February 24, 1863 just prior to the Vicksburg Campaign.  Patrick H. White was promoted from 1^st Lieutenant in  Ezra Taylor's Battery (1st Illinois Light Artillery Battery B) to become the new captain of the Chicago Mercantile Battery.  Despite being held prisoner for 14 months at Camp Ford, TX, White kept his position as Captain until the artillery battery mustered out and returned to Chicago.