21. The "'Curta "'is a small mechanical calculator developed by Curt Herzstark. 22. Nine Pascal calculators have been made, including the first surviving mechanical calculator from the 17th century. 23. More recent examples include slide rules, nomograms and mechanical calculators , such as Pascal's calculator. 24. It was the only operational mechanical calculator in the 17th century and the earliest automatic, digital computers. 25. It was a binary electrically driven mechanical calculator with limited programmability, reading instructions from punched celluloid film. 26. The desk-sized calculator was finished in 1954 and was Japan's first electro-mechanical calculator . 27. There is no doubt, however, that Atanasoff's device was unlike the mechanical calculators of the era. 28. Unchastened, brains learned to amplify themselves with pencils and paper, slide rules, mechanical calculators and electronic computers. 29. A "'difference engine "'is an automatic mechanical calculator designed to tabulate tables of numbers. 30. A new technology on display were air-powered tools along with the mechanical calculator by George B . Grant.
