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.