Full Details

Name and Model Number Brass Circular Slide Rule
Country of Origin Unknown
Date of Manufacture Unknown
Front Scales D C A
Back Scales none
Scale Length 22 cm (7 cm diameter)
Type of Rule Disc
Construction Brass. 4 parts. No cursor.
Area of Use Generic
Comment Overall diameter 7.6 cm (3")
Acquired from antique shop in Buenos Aires in 1996.
Rarity RRRR
Donor Collection of Antonio C. B. Oliveira, Brazil
Match Number 150
(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.