The Twelvetrees Calculator

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

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:
ivory, wood (unidentified) and brass (copper, zinc alloy)
type:
calculator
credit:
Bastin, Roger