1887, he had built eight machines and decided to try to
sell them. He encountered several problems. It was as
much a struggle to get the machines on the market as it
was to invent them. Also, he would have to train the operators.
(Such training, incidentally, turned into a highly
profitable sideline in later years.) According to
Felt, college professors as a rule ignored this step forward
into mechanical mathematics, and bookkeepers seemed to
think that it was an interference with their chosen vocation.
in a few years the Comptometer, advertised as "The
Machine Gun of the Office," and the Burroughs keydriven
adding and listing machines became the most popular accounting