Full Details

Name and Model Number Gravet - Lenoir
25 cm Règle à Calculer
Country of Origin France
Date of Manufacture c. 1851 - 1866
Front Scales A [ B C ] D
Back Scales S L T
Scale Length 25 cm
Type of Rule Slide Rule
Construction Closed frame boxwood, no laminate. No beveled edge. Chisel cursor missing.
Area of Use Generic
Comment Marked "GRAVET LENOIR 14 R. CASSETTE, PARIS". Address, maker and scale set dates this slide rule to 1851 to 1866.
Rarity RRR
Donor Collection of Ed Chamberlain, USA
Match Number 145
(Click Picture for Details)

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.