The Excelsior Mills in Janesville, built by Richardson in 1848, were destroyed by fire.

The evidence

• “This institution, which dates its organization from the formation of a hook and ladder company, is not unlike the fire departments of other Western towns. After the burning of Hodson's Brewery, which stood where the Doty manufacturing shops now are, on May 7, 1848, and the destruction of Richardson's Mill, on the race, in February, 1850, the few business men of ' the village organized a hook and ladder company, which was equipped in the following summer, with a truck of the most unique pattern. It was of home manufacture, the product of Hardy & Thompkins' shops, which stood on the ground now occupied by C.”

  1879-history-of-rock-county/14-rock-county-ch08-janesville.md, PDF p. 568 / book p. 572

  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

  

• “In February, 1850, the large Excelsior Mills built by Richardson in 1848 on the raceway were destroyed by fire. There was also a break at the eastern end of the upper dam, but this was shortly afterward repaired.”

  1908-brown-rock-county/26-history-of-janesville.md, Vol. 2, PDF p. 30 / book p. 544

  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