NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
The Bygrave Slide rule
From: UNK
Date: 2009 May 29, 14:39 -0700
From: UNK
Date: 2009 May 29, 14:39 -0700
It's just been drawn to my attention that in the book "Spherical Trigonometry" by J.H. Clough-Smith, on page 105, "Aquino's log tangent + log secant method" is described. It seems fairly clear that the Bygrave Slide Rule is based on this method, which talks about 'only needing tables of log secants and log tangents'. I rest my case. Bygrave must have consciously changed the name 'secant' to 'cosine' in his written descriptions. I have a .gif of this description but as a non-member I can't post it here. Peter Martinez -------------------------------------------------------- [Sent from archive by: peter.martinez-AT-btinternet.com] --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---
