|Name and Model Number||Keuffel & Esser 4079 |
|Country of Origin||USA|
|Date of Manufacture||c. 1900 - 1906|
|Front Scales||A [ B C ] D|
|Back Scales||A [BI CI] D|
|Scale Length||50 cm|
|Type of Rule||Slide Rule|
|Construction||Open frame mahogany; celluloid laminate. Metal framed glass cursor.|
|Area of Use||Generic|
|Comment||No model number on slide rule. Model #4079 determined by matching the slide rule attributes with K&E catalog descriptions.
Non-adjustable riveted end posts. Stamped with "Keuffel & Esser Co". & "Pat. Oct. 6, 1891" (the Cox patent).
This is an example of the first duplex slide rule.
|Donor||Collection of Ed Chamberlain|
(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.|