Jerome W. Briggs was promoted second lieutenant.

The evidence

• “Jerome W. Briggs, promoted Second Lieutenant July 5, 1864, First Lieutenant, September 27, 1864; A.”

  1879-history-of-rock-county/12-rock-county-ch06-politics-war-record.md, PDF p. 461 / book p. 465

  Butterfield, C. W., et al. The History of Rock County, Wisconsin: its early settlement, growth, development, resources, etc. Chicago: Western Historical Company, 1879. Cornell University Library via the Internet Archive, archive.org/details/cu31924028871585.

  Grade A: Found on a page of one of our sources

  

• “S. A., May 11, 1864; S. S. Hart, first lieutenant, promoted captain May 11, 1864; Nicholas Crotzenberg (promoted first lieutenant May 11, 1864, mustered out November 21, 1864), Charles W. Stark, Jerome W. Briggs (promoted second lieutenant July 5, 1864, first lieutenant September 27, 1864, captain August 31, 1865), A. V.”

  1908-brown-rock-county/16-military-history.md, Vol. 1, PDF p. 373 / book p. 343

  Brown, William Fiske, editor. Rock County, Wisconsin: A New History of Its Cities, Villages, Towns, Citizens and Varied Interests, from the Earliest Times, Up to Date. Chicago: C. F. Cooper & Co., 1908. 2 vols. archive.org/details/rockcountywiscon01brow, archive.org/details/rockcountywiscon02brow.

  Grade A: Found on a page of one of our sources · may repeat 1879-history-of-rock-county, so not counted as independent