English: Third "Radical" table constructed by John Napier to aid in his calculation of logarithms. The top row starts with 10⁷ and each number in that row is the previous number times 0.99. In each column the entries below the first are the previous entry time .9995. (Think of it as a modern spread sheet.) The column multiplications are carried out using one division by 2 and one subtraction per step, greatly simplifying the calculations. The logarithms of each number can then be calculated by successive addition, starting with the log of 0.9995, calculated from the second table. Adapted from John Napier (1619) w:The Construction of the Wonderful Canon of Logarithms, Blackwood & Sons ^{:p. 14)}