|Name and Model Number||Meyrat & Perdrizet |
Cercle a Calcul, Type 2b
|Country of Origin||France|
|Date of Manufacture||Patented 1880|
|Front Scales||C, D|
|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.
|Donor||Collection of Clay Castleberry, California, USA|
(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.|