Logarithm

From the Latin logarithmus, literally mathematical proportion or ratio. First devised in 1614 by the Scottish mathematician John Napier who reduced complicated multiplication and division of numbers to the simpler operations of adding or subtracting their exponents (logarithms, abbreviated logs). Diurnal proportional logs, used in astrological calculations, are based upon the ratio between hours or degrees and minutes (1/60) and can be adapted to problems involving minutes and seconds of time or arc because the same ratio exists between the two smaller units as between the larger units (hours to minutes of time or degrees to minutes of arc display the same ratio as minutes to seconds of arc or minutes to seconds of time).