Objects

The logarithmic slide rule (also known as a calculating slide rule) is a rectangular-shaped instrument made of grey plastic with a brown leather cover. The object is equipped with a scale with Arabic numerals, which are arranged in six rows along the device, and a transparent plastic plate in the shape of a rectangle. The plate is fixed to the surface of the object in such a way that it can be moved along the scales. The shape of the cover is similar to the shape of the object. It consists of two rectangular strips of leather sewn together. A seam was placed on three of the four sides, allowing the device to be slid inside.

The simple computing device was widely used by engineers until the spread of electronic tools. It is most often made in the form of a ruler with a slide and a window (like the one belonging to Marian Rzędowski), but there are also round sliders. The logarithmic slider works on the principle of adding logarithms by adding different lengths of segments marked on a sliding scale. The device allows multiplication, division, potentiation and rooting.

Marta Frączkiewicz