How did the keyboard layout we are used to, known as QWERTY after the first letters in the top row, come about? The earliest typewriters didn't use it, but it became the layout that typists learned. Christopher Latham Sholes developed typewriters and filed several patents in the 1860s, and first one that included the QWERTY pattern in 1878. The story most told about the layout goes like this:
The popular theory states that Sholes had to redesign the keyboard in response to the mechanical failings of early typewriters, which were slightly different from the models most often seen in thrift stores and flea markets. The type bars connecting the key and the letter plate hung in a cycle beneath the paper. If a user quickly typed a succession of letters whose type bars were near each other, the delicate machinery would get jammed. So, it is said, Sholes redesigned the arrangement to separate the most common sequences of letters like “th” or “he”. In theory then, the QWERTY system should maximize the separation of common letter pairings.
But there are problems with this story. For one thing, the combination "er" is too common to have the two letters side-by-side. And people of a certain age know that even 20th-century typewriters with mechanical levers would tangle if you typed too fast. Recent research turns up a different theory, which involves telegraph operators. Read how these operators helped to determine the way we type today at Smithsonian. Link