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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Robert VanderPol II
Date: 2023 Feb 9, 20:53 -0800
I have an 8" Atlas with a 30-ring spiral equivalent to a 360" I believe. 4 decimal places, and can estimate to the nearest 1/4 of that for the whole range.
I also have an Otis-King, tube about 5" long x 1" diameter that telescopes. 2 normal & 1 logrithmic scales for powers printed as a helix, equivalent to a 42" straight rule. 3 decimal places and can estimate to 4 places for most or all of the range.
Ah, the ingenious stuff those folks of yore invented and used.
On slide rules
From: Alan S
Date: 2023 Feb 6, 14:40 -0800Ed:
Have a few myself, fascinating devices, and in an ever increasingly complex world, the "stick" rules had only 2 moving parts. The bambo rules are self lubricating I understand. As for the metal ones, a bit of oil seems to do the trick.
Moving on, did you ever come across the circular type. They were made by Gilson as I recall. The 8" diameter rules, with the C scale being outboard, provide a C scale 24" long, which in theory would be more accurate than the standard 10" stick type. The circular slide rule never seemed to have taken off though. Curious, but then the stick type might have been to well established to buck. Take care.
Alan
