The Twelvetrees Calculator

Made:
c. 1911 in Manchester
inventor:
Walter Noble Twelvetrees
maker:
J Halden and Company Limited

Calculator, The Twelvetrees Calculator for reinforced concrete beams, for estimating compressive versus tensile strength, invented by W. Noble Twelvetrees, made by J. Halden & Co. Ltd., housed in velvet lined leather carrying case, includes instruction manual, ex Hull Joint Dock Committee.

Details

Category:
Tools of the Trade & Personal Accessories
Object Number:
2005-7395
Materials:
brass (copper, zinc alloy), ivory and wood (unidentified)
type:
calculator
taxonomy:
  • furnishing and equipment
  • tools & equipment
credit:
Bastin, Roger