Full Details

Name and Model Number Noble’s double rule
Country of Origin UK
Date of Manufacture c1895
Front Scales Routledge variant
Back Scales Engineering and steel measure
Scale Length 11”
Type of Rule Other
Construction Boxwood & brass
Area of Use Other
Comment 2-foot, 2-fold used in engineering.
Noble’s double slide rule is one of very few 2-foot, 2-fold slide rules to have a slide
on both legs of the rule, one each side. Noble’s rules are unusual in using a 5 – 50 ‘D’
scale. This particular example is unusual in having extra width on one of the legs, so that
additional scales could be included, it may also be a prototype as it carries Noble’s name
under one slide. There appears to be several variants of the double rule, mostly with equal
width legs as the majority of the 2-2 rules.
Rarity RRRR
Donor Collection of an English gentleman
Match Number 54

RR = Rare -- 1 of 25 collectors has one; it may take a year to find an example in the marketplace.   
RRR = Very rare -- only very few known to collectors; may take several years before one comes up for sale.   
RRRR = Extremely rare -- a museum piece; unlikely that an example will ever come up for sale.