NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Longitude sight, South Pacific, 1864
From: Brad Morris
Date: 2018 May 16, 20:09 -0400
From: Brad Morris
Date: 2018 May 16, 20:09 -0400
Hello Charles
Logarithms permit multiplication by addition. That is, instead of multiplying two numbers together, we add the logarithms of those two numbers and then take the inverse logarithm to find the same result as pure multiplication!
Similarly, one can divide two numbers by the subtraction of logarithms of those numbers and then taking the inverse log.
It is a far less error prone and gets rid of those pesky, "error prone" multiplication tables.
Slide rules are typically logarithms realized in a physical medium, if that's any help in visualizing this!
Brad
On May 16, 2018 7:47 PM, "Charles McElhill" <NoReply_McElhill@fer3.com> wrote:
I have a question regarding the use of logarithms. What was the advantage for 19th century navigation?
You see this a lot in old navigation text. Was it just to simplify interpolation ? Thanks
