NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: David Pike
Date: 2016 Jan 14, 16:41 -0800
I’ve got the loan of a Bygrave Position Slide Rule MkIIA from the Royal Institute of Navigation for a couple of months (photos below). Apparently, they had two, a good one and a poor one. Unfortunately, I was only able to find the poor one; nobody seemed to know what happened to the good one. It carries the inscription that it was produced by the Air Ministry Laboratory South Kensington in August 1920. If the number was ever filled in, it’s long since rubbed off. I’d like to teach myself to use it prior to possibly making a copy for myself with plastic piping. Is the best set of usage instructions those on Gary’s Freddie Noonan page? Also, does anyone know where I can find a photo or print out of the explanation off the side of the MkIIA? Finally, does anybody know what went down the inside of the cylinders? All I can see is the remains of a brass chain. DaveP
