Set of four ivory triangular rules in cardboard case

1850-1869 in London
William Ellis Metford
Pastorelli and Company

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Set of four ivory triangular rules by Pastorelli and Co., London, stamped with various conversions. Overhead view of
Science Museum Group Collection
© The Board of Trustees of the Science Museum

Set of four ivory triangular rules, stamped with various conversions, arranged by William Ellis Metford, and made by Pastorelli and Company, London, 1850-1869

This is the rule for someone who needed, or loved to have, a great deal of numerical information. Each of the 12 available rectangular surfaces and half of the triangular ones are crammed with figures and scales. There are plain rules in various divisions of the inch, scaling rules for map-reading, trigonometric lines and trigonometric equations, the areas and circumferences of circles and spheres and equations for finding areas, expansion coefficients and specific gravities of various metals and water, conversion scales for English to French and Rhineland feet, and to metric, information for ranging, gravity, and equations of motion.


Object Number:
cardboard, ivory, paper (fibre product)
overall (in case): 21 mm x 165 mm x 37 mm, .144kg
triangular rule (mathematical)
  • furnishing and equipment
  • measuring device - instrument
  • ruler - measuring device
  • furnishing and equipment
  • container - receptacle
Christie's South Kensington Limited
Permanent collection

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