brass draftsman's rule
Date: circa 1850
Inventory Number: DW0459
Classification: Rule
Subject:
Maker: Troughton & Simms (1826 - 1923)
Cultural Region:
Place of Origin:
Dimensions:
0.2 x 31.7 x 2.7 cm (1/16 x 12 1/2 x 1 1/16 in.)
Material:
DescriptionRule is a flat rectangular brass plate with one darker brass edge. Various scales are engraved in black on the front side of the rule. The darker edge is divided into thirty-six equally spaced increments by engraved lines. Two sets of number scales accompany the lines on the darker edge. The outermost scale increases from 0 to 36. Each of these increments is further subdivided in ten by smaller engraved lines, every fifth of which is longer. The numbers of the innermost scale are slightly smaller. They begin with 36 and decrease from left to right until 0.
The lighter part of the rule is also divided into 36 equal increments by engraved lines. They are also marked from 1 to 36, increasing from left to right. The numbers are one-off of the outermost scale of the dark edge such that 1 is below 2, 2 is below 3, and so forth. Each increment is further subdivided into ten rows by horizontal engraved lines that run the length of the rule. Every second of these lines is marked 2, 4, 6, and 8 at the leftmost end of the rule. The leftmost increment of this scale is divided by ten transversal lines that angle towards the bottom rightmost corner. The scale on the lighter component of the rule is called "Gunter's Vernier".
The lighter part of the rule is also divided into 36 equal increments by engraved lines. They are also marked from 1 to 36, increasing from left to right. The numbers are one-off of the outermost scale of the dark edge such that 1 is below 2, 2 is below 3, and so forth. Each increment is further subdivided into ten rows by horizontal engraved lines that run the length of the rule. Every second of these lines is marked 2, 4, 6, and 8 at the leftmost end of the rule. The leftmost increment of this scale is divided by ten transversal lines that angle towards the bottom rightmost corner. The scale on the lighter component of the rule is called "Gunter's Vernier".
Signedengraved on the back in black script: Troughton & Simms, London.
FunctionRule can be used as a straight edge for drawing or measuring straight lines. The transversal lines at the leftmost end are for increased precision. David P. Wheatland noted that "this is the type of reduced scale that architects use but usually 1/4 "to the feet"."
ProvenanceDavid P. Wheatland purchased rule from Ellis Shaw in 1942.