Exposition
Technological Evolution
Rule Calculus
( 1614 ) John Napier discovered that it was possible do multiplications and divisions by adding and subtracting logarithms. This saved calculation processing time, but it was very tedious.
Edmund Gunter proposed drawing a numbered line in which the positions of numbers were proportional to their Logarithms. This led to the slide rule. The computational power of these devices increased over time: they could be used to multiply, divide, calculate powers, square roots, trigonometric functions, logarithms and interest and amortization rates.
The slide rule was a mechanical device commonly used to perform calculations in the late 17th century. It survived for 300 years until the appearance of the pocket scientific calculator in the 1970s.