Full Details


Name and Model Number GRAPHOPLEX 691
NEPERLOG HYPERBOLIC
Country of Origin FRANCE
Date of Manufacture abt. 1960
Front Scales L P Ch A B T<45 ST S C D Th Sh2 Sh1
Back Scales LL01 LL02 LL03 DF CF CIF K CI C D LL3 LL2 LL1
Scale Length 25 cm (10 inches) [ 338x48.7x4.2 mm ]
Type of Rule Slide Rule
Construction Plastic
Area of Use Generic
Comment Graphoplex, based in Paris, was the main slide rule manufacturer in France. Some slide rules were also redistributed to the USA via a Koh-I-Noor label.
Rarity RRR
Donor Collection of Gonzalo Martin, France
Match Number 377
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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.