Full Details

Name and Model Number	Keuffel and Esser 4100
Country of Origin	USA
Date of Manufacture	Listed in K+E catalog 1900- 1901 (early 1900’s)
Front Scales	Unmarked - has horizontal differences and vertical distance calculations
Back Scales	none
Scale Length	25 cm (9.8 inches)
Type of Rule	Slide Rule
Construction	Celluloid on Mahogany
Area of Use	Topography
Comment	K&E's first linear stadia slide rule
Rarity	RR
Donor	Collection of Clay Castleberry
Match Number	286
Thumbnail (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.