In The Shallows, Nicholas Carr talks about the Danish-made Malling-Hansen Writing Ball that Friedrich Nietzsche used as his vision was failing and he was worried about having to give up his writing (17). Here’s an image of this Writing Ball from John Farrier’s “Early Typewriter: The Malling-Hansen Writing Ball,” http://www.neatorama.com/2010/10/18/early-typewriter-the-malling-hansen-writing-ball/).
Malling Hansen’s Skrivekugle (Writing Ball), 1865
The Writing Ball’s inventor, Rasmus Hans Johan Malling-Hansen, who patented this device in 1871, was the director of the Denmark’s institute for the hearing impaired in Copenhagen. You can read more about the device at the Neatoshop website.