Full Details


Name and Model Number Wellington, of London
A Sector
Country of Origin England
Date of Manufacture 1845 to1855 When Wellington was in business
Front Scales Inches L S C L S C inches (12 inches when folded out straight)
Back Scales I S T T S T T T S N
Scale Length 30 cm (12 inch)
Type of Rule Rule
Construction Solid elephant ivory – brass hinge
Area of Use Technical
Comment Sector – Galileo called his a compass of equal proportions in 1605-10. Used most often for astronomy, navigation, surveying – with proportional dividers. Note the tiny little brass inserts, for using proportional dividers – also note the scales are machine divided and letters and numbers are stamped by hand.
Rarity RRR
Donor Collection of Clay Castleberry
Match Number 329
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In conjunction with our 'donors' we assign a rarity rating to each item, based on the system devised by Herman van Herwijnen
(1929 - 2004), renowned Dutch collector, author, and creator of Herman's Archive, a collection of 5,000 slide rule images on CD.
• RR = Rare - 1 of 25 collectors has one; it may take a year to find an example in the marketplace.
• RRR = Very Rare - only a few known to collectors; may be several years before it comes up for sale.
• RRRR = Extremely Rare - a museum piece; unlikely that an example will come up for sale.