The sector, also known as a proportional compass or military compass, was a major calculating instrument in use from the end of the sixteenth century until the nineteenth century. It is an instrument consisting of two rulers of equal length joined by a hinge. A number of scales are inscribed upon the instrument which facilitate various mathematical calculations.
Reeves Scale Rulers
Reeves & Sons Ltd, 1891-1972: Following the death of Henry Bowles Wild in 1882, his brother, Charles K. Wild, became head of the business, and was followed in 1896 by his son, Charles J. Wild (1865-1923), who was Managing Director until 1923. Reeves became a private company in about 1883 and seven years later a public limited company. Reeves & Sons Ltd, 1891-1972.
Scale Rulers - W H Harling
These scale rulers were made by W H Harling in London for E Esdale and E Esdale and Sons.
I estimate that they are circa 1920.
They were donated by John Webber
Slide Rule - Concise
This is a circular slide rule No 28 complete with case and instruction booklet.
Concise specialized i the manufacturer of circular slide rules under the name Concise Co. Ltd. from 1959 to 1966.
This item was donated by John Webber
Slide Rule W & G
This slide rule was made by W & G and is the dual face model 432.
The manufacturers were A.E.White and J.D.Gillespie ( W & G) an Australian Company based in Melbourne, Australia.
They only started to produce slide rules after WW2.
This item was donated by John Webber.