|Name and Model Number||Coggeshall-Dialling rule|
|Country of Origin||UK|
|Date of Manufacture||c1750?|
|Front Scales||Timber Calculating scales – note Girt Line|
|Back Scales||Scamozzi sector lines|
|Type of Rule||Other|
|Construction||Boxwood and Brass|
|Area of Use||Other|
|Comment||a 2-foot, 2-fold rule.
Not sure of its area of use: perhaps this might be more architectural?
The unusual mixture of scales on the two sides of this early 2-foot, 2-fold slide rule
by an unknown maker are difficult to rationalise! The front appears to have the standard
suite of Coggeshall Timber and calculating scales aimed at calculating the volume of usable
timber in a standing tree, while the unusual sector scales on the back with unknown gauge
points may have something to do with calculating roof trusses – but that is something I
would not set in stone! Part of the delight of these 2-2 slide rules is the unusual
combinations one finds, a Dialling and Routledge is also known, speculating what it was
used for or by whom, is interesting!
|Donor||Collection of an English gentleman|
|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.|