Description and Notes:
The above picture shows the two sides of this boxwood slide rule. This type of folding slide rule is generally known as the Carpenter's slide rule. A booklet about its history and use was first published by the maker, John Rabone & Sons in 1879, currently the third edition of which (originally published in 1880) is still avaliable as facsimile copy. More information about this kind of rules can also be found in A Source Book for Rule Collectors.
This well made, high quality rule has a built in protractor and it is dated to c1860 as John Rabone was working from 1825 to 1860. Also according to the Webster Signature Database, the firm "J. Rabone and Sons" was flourished around 1858 to 1860.