Full Details

Name and Model Number Anderson's
Improved Slide Rule
Country of Origin England
Date of Manufacture ~1900
Front Scales cms/ 1 extended scale [1 extended scale] 1 extended scale / ins
Back Scales None
Scale Length 30 cm
Type of Rule Slide Rule
Construction Mahogany and Plastic
Area of Use Generic
Comment Manufactured by L. P. Casella
Rarity RRR
Donor Collection of Rod Lovett
Match Number 1

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.