This prototype is in the Dietz Collection at the Milwaukee Public Museum.
Gilbert Arnold Brady, a Chicago manufacturing agent and real estate broker, and Francis Fullmer Warner, a Chicago patent solicitor, applied for a patent for their index machine on November 17, 1877, and it was issued on April 9, 1878, just after Brady's 51st birthday and just before the Remington 2, the first typewriter with a shift device, went on sale. It was the 56th US patent since 1829 related to writing machines.
Brady was born in New York City on April 6, 1827, while Warner was born in Waterloo, New York, in 1840. Brady moved to Illinois and was a merchant in Little Rock in 1850 and Manlius in 1860. He was in Chicago by 1870. In the interim, Warner had served in the Civil War. The pair died within months of one another, Warner on January 7, 1897, in New York City, aged 56, and Brady in Chicago on November 14, 1897, aged 70.