### „If a first sine be multiplied into a second producing a third, the Logarithm of the first added to the Logarithm of the second produces the Logarithm of the third. So in division, the Logarithm of the divisor subtracted from the Logarithm of the dividend leaves the Logarithm of the quotient.“

— John Napier Scottish mathematician 1550 - 1617

Appendix, The relations of Logarithms & their natural numbers to each other

The Construction of the Wonderful Canon of Logarithms (1889)