Accession No
3750
Brief Description
parallel rule, 1/4 20th C
Origin
England
Maker
Class
drawing
Earliest Date
1900
Latest Date
1925
Inscription Date
Material
wood (boxwood); metal (brass, copper alloy)
Dimensions
length 383mm; breadth 69mm; thickness 17mm
Special Collection
Provenance
Donated, 1990.
Inscription
‘CapT Field’s
Improved’ (obverse)
‘S.G.H. Bowyer’ (MS on reverse)
Description Notes
Pair of boxwood parallel rules with bevelled edges, joined by shaped brass strips with copper alloy knobs. Rectangular protractor on three sides divided [0] - 90˚ - [0], numbered by 10˚, subdivided to 1˚. Bottom edge carries rhumb scale for WSW to ESE (through S), marked with SW, S and SE, divided to quarters of a by-point.
Condition fair (one knob heavily corroded, at least one rivet loose); complete.
References
Events
Description
Parallel rule
Used by architects, engineers, cartographers and on nautical charts, the parallel rule is used for drawing parallel lines accurately. It is also used in conjunction with a scale rule for producing orthogonal drawings (with lines in non-parallel direction as well). The pivoting links can be extended to the required distance, but this makes the instrument liable to error for larger drawings because the extension is changed by hand, and can be varied accidentally.
18/10/2002
Created by: Saffron Clackson on 18/10/2002
FM:44441
Images (Click to view full size):
