Napier's Bones (history of computer)

 Napier's Bones 

The next manual calculating device logarithms was invented by John Napier's Bones in (1550-1617).

The use of logarithms enabled him to transform multiplication and division problems into problems of addition and subtraction. The word logarithms is a combination of two Greek word, loges (means ratios) and arithms ( means number).When he first invented these numbers he had no idea of base.

later in 1624, professor Hurry Briggs of  Gresham college, London defined base and tabulated logarithms of base "e" ("e" is a number whose value is approx. 2.710 and base 10). The invention of logarithms was an important breakthrough in the development of mathematics and computing device.