Blickensderfer No. 5the typewheel

George Blickensderfer's machine is one of the great what-ifs of typewriter history. Instead of a basket of type-bars it uses a single cylindrical type-wheel that rotates to the right character and strikes through an inking roller, which means the type element is interchangeable (you could swap typefaces) and the whole machine could be small and light, a genuine portable in the 1890s. The No. 5 was the popular early model, often sold with Blickensderfer's own “Scientific” DHIATENSOR keyboard laid out by letter frequency, though QWERTY versions exist too. It is more a fascinating antique than a daily writer, but the type-wheel idea it pioneered is essentially what IBM revived, mechanically rhymed, in the Selectric's golf ball sixty years later.