UNUSUAL COMPARISON RULE
Stock Number: 9279
For sale antique comparison rule by Troughton & Simms. The rule is engraved with scales of English and Spanish inches, and old French inches. Contained in the original mahogany case.
13-1/2 inch (34 cm) long
c. second quarter 19th century
Country of manufacture
UK and Ireland
UNUSUAL COMPARISON RULE, English, c. second quarter 19th century, signed “Troughton & Simms, London.” This 13-1/2″ (34 cm) long brass rule is 5/16″ square in cross section, engraved on the four sides with scales of English inches from 0 to 12 by tenths, Spanish inches likewise, old French inches (the old “Pouces du Roy”) from 0 to 12 by twelfths, and “Decimetre’s” from 0 to 3 by hundreths (i.e., by millimeters). Condition is excellent, complete with its original slightly domed mahogany case.
The partnership of Edward Troughton and William Simms commenced in 1826, and was a long-lived manufactory of all manner of optical and mathematical instruments. We have had a number of interesting comparison rules, but none quite like this. It may have assisted in English trade with France and Spain, and was made at a time when the old French inch measure was not yet fully abandoned in favor of the metric system
Ask the Dealer
David and Yola Coffeen both have enjoyed academic careers, as planetary astronomer and as linguist/educator. But since 1982 (yes, 1982!) they have been full-time dealers in early scientific and medical instruments, under the name Tesseract. Selling primarily by catalogue (over 100 issued so far) they also have a web presence at www.etesseract.com, and can be contacted at email@example.com.