Pascaline

Pascaline, also known as Pascal's calculator or arithmetic machine, is an early mechanical calculator designed by Blaise Pascal in the 1640s in France. It was developed to help his father, a tax collector, perform simple arithmetic more quickly and accurately. The device is a compact assembly of gears and wheels intended to carry out addition and subtraction by turning a crank.

Most Pascalines use a row of decimal wheels, each corresponding to a digit place. The user enters numbers by turning a set of dials or a crank; each wheel advances to the next with carries automatically when a wheel overflows from 9 to 0. This carry mechanism enables additions of multi-digit numbers and also supports subtraction by complement techniques. Multiplication and division were not implemented as single operations, but could be done through repeated additions or using layout methods.

Historically, the Pascaline is one of the earliest widely known mechanical calculators and among the first devices to offer automatic carry between digit places. Although not a mass-produced instrument by modern standards, several models were manufactured in the mid-17th to 18th centuries and later influenced the development of later calculating machines, including the works of Gottfried Wilhelm Leibniz.

Variants varied in size and capacity, with several surviving examples preserved in museums around the world. The machines were often expensive and required careful maintenance, which limited their widespread adoption but demonstrated the feasibility of automatic computation.

Today the Pascaline is regarded as a landmark in the history of computing, illustrating the shift from hand arithmetic to mechanical computation and influencing later designs, including Leibniz's stepped reckoner.