Circular index typewriters

The linear index had one great advantage over the square index typewriter. It was the easiest and cheapest to produce. But working on a linear index machine is tiring when you constantly need to shift the index pointer over a distance of up to 8 inches.

The semi-circular index, like the American 2 and the World, made life a bit easier. Instead of using the arm, a movement of the wrist was now enough to select letters that were wide apart on the index strip.

The completely circular index went another step further. Here all one usually had to do was turn a knob to select the right character.

Circular and semi-circular indexes were more widely used than the linear index.