Comptometer
Comptómetro
- Date
- 1887 · confidence high
- Place
- Chicago, Illinois, United States
- Credited to
- Dorr Felt
- Field
- Knowledge & symbols
What it is
The first commercially successful key-driven mechanical calculator, patented by Dorr Felt; each key adds or subtracts its value to the accumulator as soon as it is pressed, letting skilled operators enter whole numbers with several fingers at once.
What it led to
- Spread of key-driven calculators in offices and businesses
- Training of operators specialized in fast mechanical calculation
- Precedent for later electromechanical and electronic calculators