Full Details

Name and Model Number Cameron’s rule
Country of Origin UK
Date of Manufacture ~ 1852
Front Scales Unknown
Back Scales Normal 24” measuring rule
Scale Length 11"
Type of Rule Other
Construction Boxwood & Brass
Area of Use Other
Comment 2-foot, 2-fold with calliper for unknown use.
Paul Cameron of 87 London Street, Glasgow was a mathematical instrument maker who took over
from Robert Finlay and worked between 1851 and 1854. What this rule was for is unknown.
The unusual calliper (the slide will only move in one direction) has not been seen elsewhere
and the scales on the slide and those on the stock which are labelled Tan and Sine do not appear
to relate to anything else. There are also a plain scale and two other scales of unknown function
on the second arm. The reverse of the rule is calibrated in various fractions of an inch for the
24” length of the two arms.
Rarity RRR
Donor Collection of an English gentleman
Match Number 90

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.