In its most basic form, the slide rule uses two logarithmic scales to allow rapid multiplication and division of numbers.These common operations can be time-consuming and error-prone when done on paper.William Oughtred and others developed the slide rule in the 1600s.
Joseph Dixon was another early American pencil maker—his company’s Ticonderoga pencils are the gold standard today.
The slide rule is used mainly for multiplication and division, and also for "scientific" functions such as roots, logarithms and trigonometry, but usually not for addition or subtraction. These scales are used for mathematical computations.
They have a standardised set of markings (called scales).
Scott they ceased making instruments to the traditional pattern in 1929 and changed to flat pattern ones.
In 1964, having merged with Blundell Rules Ltd to form Blundell Harling, they moved to the Blundell premises in Weymouth.