A large, clear black-and-white image turned up this morning, but there are no details with it (the eBay seller dates the photo from 1930). According to Wilf Beeching's Century of the Typewriter, this is the Sholes and Glidden "Experimental Model of 1873". I wonder where it is? Milwaukee, perhaps?:
In Richard Current's The Typewriter and the Men Who Made It, he has this patent image and explanation:Or could it be this one, patented in 1876 and co-credited to Matthias Schwalbach?