|Name and Model Number||Simpson’s rule|
|Country of Origin||UK|
|Date of Manufacture||c1905|
|Front Scales||Noble scales and tables|
|Back Scales||Routledge engineering with gauge points inc Aluminium, conversion factors, |
no steam gauge points
|Type of Rule||Other|
|Construction||Boxwood & German silver|
|Area of Use||Other|
|Comment||A 2-foot, 2-fold rule used in Engineering.
Abraham Simpson’s slide rule from sometime in the early 20th century is a strange mixture
of Routledge engineering and Noble’s designs of engineering 2-foot, 2-fold slide rules.
Engineering calculation is carried out on the one side; the second allows weight of steel
sheet etc to be done as on a Noble rule. Simpson included some calculations not possible
on the other two designs. Alfred Harper of Birmingham (1900 – 1925) is not a well known maker,
the factory burned down in 1925.
|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.|