Full Details

Name and Model Number	Billeter, Ernst Blitzrechner
Country of Origin	Switzerland
Date of Manufacture	c. 1905
Front Scales	Circular C & D scales
Back Scales	none
Scale Length	4 m
Type of Rule	Disc
Construction	12.4-cm dia.; varnished paper scales on hard board disks; nested disk type; metal ring at outside edge; turning knob for inner disk on the back.
Area of Use	Generic
Comment	Ernst Billeter was a brother of Julius Billeter.
Rarity	RRRR
Donor	Collection of Ed Chamberlain
Match Number	277
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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.