The Fuller Cylinder model 1 has a logarithmic scale of 12.50m. Model 2 has two spirals.

The machine consists of an inner cylinder which can rotate on its axis on which 60 sections of a logarithmic scale are printed.

This logarithmic instrument is built in the form of a pocket watch, and uses the so-called “BOUCHER” method.

This is the equivalent of a straight slide rule of 1.72 meter long. The K model can perform multiplications, divisions, proportions and percentages. The L model incorporates the features of the K model and can do powers and roots.

The slide rule can do multiplications, divisions, powers and extractions of roots and trigonometric calculations. The back of the rule shows the trigonometric functions: sine, cosine, and tangent in a window.

This instrument is ideally suited for processing powers and square roots and cube.

Circular slide rules have a continuous scale, which reduces the number of manipulations.

This machine is used in medicine to determine the relationship between the volume of the rib cage and its air holding capacity.

This machine works just like a straight slide rule. The circular slide introduces different ergonomics and is more compact than a straight rule.