In 1866

"All the agricultural and mineral wealth of the great West turns toward Chicago, as certainly as the needle to the magnet." {745}

John B. Rice was mayor. {770}

My great-grandfather Charles Schriber, just back from the Civil War, was a salesman for soda water manufacturers W.H. Hutchinson & Sons at 243 West Randolph. {1063}

The Newberry Library's ever-growing Chicago Ancestors site now includes a browseable PDF version of Edwards' Annual Director [sic] to the Inhabitants, Institutions, Incorporated Companies, Manufacturing Establishments, Business, Business Firms, etc., etc., in the City of Chicago, for 1866 (Chicago: Edwards, Greenough, and Deved, 1866).

Even if you have no research targets in its range, the ads are an education in themselves. Enjoy.