Full Details

Name and Model Number Léon Lalanne's "New slide rule with a glass envelope"
Country of Origin France
Date of Manufacture 1851
Front Scales Cos Sin [B B] Tan Cot A [B B] D
Back Scales D [C C] D with numerous gauge marks
Scale Length 24.7 cm
Type of Rule Slide Rule
Construction Paper scales and cardboard slide sandwiched between two glass plates
Area of Use Generic
Comment Developed as an inexpensive slide rule for high school students.
See details at https://www.nzeldes.com/HOC/Lalanne.htm
Rarity RRR
Donor Collection of Nathan Zeldes
Match Number 411
(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.