Charles Babbage was born on 26th December, 1791, at Totnes in Devonshire. He was entered at Trinity College, Cambridge, on 21st April, 1810, and resided there from October. He had at an early age shown a taste for mathematics, and was already acquainted with the works of La Croix and other continental mathematicians when he went to Cambridge. The first idea of a calculating machine occurred to him when a student at Cambridge in 1812 or 1813. He was familiar with the method of Differences, and knew that by that method Logarithmic and many other Tables could be produced by simple addition, and he saw that if a machine could be constructed to perform only simple addition, such tables could be produced mechanically. The idea seems to have lain dormant for a time, but some years afterwards, when he went to Paris, he studied the details of the arrangement by which the celebrated French Tables had been computed under the direction of Prony, and he came in contact with Didot, from whom he purchased at a high price a copy of his stereotyped Table of Natural Sines and their Differences, to twenty places of figures. By permission of the French Board of Longitude, he copied the Logarithms to fourteen places of figures of every 500th number from 10,000 to 100,000 from the Tables deposited in the observatory at Paris. In 1819 he was working at the subject (p. 42), and on 14th June, 1822, he announced to the Astronomical Society that he had completed a machine of two orders of differences, capable of producing tables of squares, triangular numbers, values of x2 + x + 41, &c. (p. 211).