Page from Vlacq's logarithmic tables, 1670.
© Science Museum / Science & Society Picture Library
Adrian Vlacq's (1600-1667) tables, first published in 1628, formed the basis of tables for many years, due to their relative lack of errors. This French edition, published as 'Tables de sinus, tangentes, et secantes' ('Tables of sines, tangents and secants') published in 1670, belonged to British mathematician and computing pioneer Charles Babbage (1791-1871) whose private collection contained over three hundred volumes. He was a fastidious analyst of tabular error. Mathematical tables were an aid to those profesions which required the performing of calculations demanding many figures of accuracy. Logarithms made the manipulation of large calculations simpler by adding or subtracting the index of two numbers and looking up the result in tables.