Full Details

Name and Model Number Meyrat & Perdrizet
Cercle a Calcul, Type 2b
Country of Origin France
Date of Manufacture Patented 1880
Front Scales C, D
Back Scales none
Scale Length 12.5 cm
Type of Rule Watch Type
Construction Nickel? German silver?
Area of Use Generic
Comment Serial no. 327. Type 2b. Has no watch movement and has open back.
It is believed that very few of this model exist.
The later and more common Type 1 has a watch movement.
Rarity RRRR
Donor Collection of Clay Castleberry, California, USA
Match Number 232
(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.