A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2015 Mar 9, 15:27 -0700
I’ve found a copy of 1794 edition (if my reading of roman numbers is correct) of The New Practical Navigator by John Hamilton Moore on line. If TNPN was first published in 1772, it’s possible that a slightly earlier edition was used by William Bligh during the open boat journey in 1789, and I wanted to see what CN and plane sailing was available to him. It took me a while to figure out the ‘Artificial Sine, Co-sine and Tangent Tables’ at Table V. They would appear to be five figure, base 10, log tables of the sines, co-sines, and tangents of the various angles plus 10.00000. This is somewhat different to the bar system of noting logs of numbers less than unity that I was taught at school. Can anybody tell me which came first? Was the + 10.00000 system designed first to make life simple for mariners or was the bar system designed first to make life simple for school children.