Full Details


Name and Model Number Fowler "Magnum"
Long Scale Calculator
Country of Origin England
Date of Manufacture 1927
Front Scales Short C scale A A L six long C scales sine sine tangent Tangent.
Back Scales None
Scale Length 124 cm (49-51 inches)
Type of Rule Watch Type
Construction Glass face, 4 inch metal body, two turning knobs
Area of Use Generic
Comment The long scale gives approx 4 place accuracy, which is very high for a slide rule
Rarity RR
Donor Collection of Clay Castleberry
Match Number 336
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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.