‘The Fuller Calculator’ (1945): a long-scale cylindrical slide rule which consists of a cylinder which can be rotated and moved up and down around an inner cylinder held by a handle and is provided with three brass pointers or indexes. The logarithmic scale is arranged spirally on the outer cylinder and is the equivalent of a straight scale of 500 inches making it possible to obtain four figure accuracy in a result. Besides the operations of multiplication and division, results requiring reciprocals, powers, roots or logarithms of numbers can be obtained. The wooden case also acts as a support when the instrument is in use.
The slide rule was used not just by engineers but also by actuaries and other professions requiring greater accuracy.
The ‘Fuller Calculator’ was patented by George Fuller MICE in 1878.
For more information on ‘Fuller’ calculators go to https://en.wikipedia.org/wiki/Fuller_calculator .