Comptometers like this are hard to find. They were available for a very long time, almost a hundred years, but they haven't survived well since being replaced by calculators and computers. This one looks to be in amazing condition. It's still functional.
- Fact 1: This particular calculator is called a Comptometer, and they were the most commercially successful key-driven mechanical calculators.
- Fact 2: Comptometers were used all the way up until the 1990s, when advances in computer technology made them obsolete.
- Fact 3: In 1889, the inventor of the Comptometer added a printing mechanism and was granted a patent for the Comptograph, which was a precursor to modern-day adding machines.
- Fact 4: The Comptometer was invented by Dorr A. Felt in 1887, who was paid a $6/week salary to build his early production models.
- Fact 5: The mechanical calculator was first developed in 1642, but wasn't commercially successful until 1851.