ital computer, was devised in 1642 by the French philosopher Blaise Pascal. This device employed a series of ten-toothed wheels, each tooth representing a digit from 0 to 9. The wheels were connected so that numbers could be added to each other by advancing the wheels by a correct number of teeth. In the 1670s the German philosopher and mathematician Gottfried Wilhelm von Leibniz improved on this machine by devising one that could also multiply. The French inventor Joseph Marie Jacquard , in designing an automatic loom, used thin, perforated wooden boards to control the weaving of complicated designs. During the 1880s the American statistician Herman Hollerith conceived the idea of using perforated cards, similar to Jacquard's boards, for processing data. Employing a system that passed punched cards over electrical contacts, he was able to compile statistical information for the 1890 U.S. census. b) The Mother of all Computers Also in the 19th century, the British mathematician and inventor Charles Babbage worked out the principles of the modern digital computer. He conceived a number of machines, such as the Difference Engine, that were designed to handle complicated mathematical problems. Many historians consider Babbage and his associate, the British mathematician Augusta Ada Byron (Lady Lovelace, 1815-52), the daughter of the English poet Lord Byron, the true inventors of the modern digital computer. The technology of their time was not capable of translating their sound concepts into practice; but one of their inventions, the Analytical Engine, had many features of a modern computer. It had an input stream in the form of a deck of punched cards, a "store" for saving data, a "mill" for arithmetic operations, and a printer that made a permanent record. c) Early Computers Analog computers began to be built at the start of the 20th century. Early models calculated by means of rotating shafts and gears. Numerical approximations of equat...
