Full Details

Name and Model Number Tavernier-Gravet
Butterfat Slide Rule
Country of Origin France
Date of Manufacture c. 1910
Front Scales Extrait [ Beurre ] Densité
Back Scales none
Scale Length 22 cm
Type of Rule Slide Rule
Construction Closed frame boxwood; 23 cm x 3.3 cm. Scales printed directly on wood surface.
Area of Use Other
Comment For the dairy industry to determine the butterfat content of milk.
Taverinier-Gravet printed on lower narrow edge.
Uncertain if any other examples are known.
Rarity RRR
Donor Collection of Ed Chamberlain
Match Number 192
(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.