Magnet features an advertisement from 1870 promoting the Letz & Co. Chicago Iron Works. According to the advertisement, Letz manufactured "iron fronts for buildings, bank vaults and doors, jail doors and cells, iron fencing, grating, shutters, bolts, window caps and sills and iron work of every description." Founded in 1848 on Wells street, by 1870 the company occupied a 3-story facility at 84-92 S. Franklin St. It incorporated in 1867 and in 1870 was owned by George F. Letz, William H. Chenoweth and August Gabriel.
The original company, F. Letz & Son, was founded by George's father, Frederick (c1810-1876?), one of the first three members of Chicago's Board of Public Works, formed in 1861. In 1863 Frederick Letz was one of the commissioners who officiated over the construction of a 2-mile tunnel under the bed of Lake Michigan to bring fresh water into the city, a project that included the Chicago Water Tower. That same Board pressured Chicago's mayor to purchase 50 additional acres to make Lincoln Park. Frederick's company was linked with other's in Chicago's ironworks history, including men named Johnson, Burling and Jacob J. Volrath. In the mid 1850s he sold his ornamental casting foundry to Nathaniel Bouton. Frederick retired in 1869 and his son George, who had joined the company in 1857, took over. Chenoweth joined the company in 1855 as superintendent and foreman. August Gabriel joined in 1858 as a foreman.
In 1869 the company put in the lowest bid, $85,000, to do the iron work on Wisconsin's new state capital building; no clue whether they got the contract. At the time of this ad George Letz may have been developing his fireproof metal roof that he would patent in 1872. It would not be his first patent; in 1861 George patented a rolling iron shutter. It appears August Gabriel started his own company; by 1876 he was the proprietor of Industrial Iron Works on Monroe street.