Abacus, 10 columns long. 2/5 abacus: 2 top beads to 5 bottom beads (70 beads in total).
The instrument consists of a rectangular wooden box with metal reinforced corners and two metal handles on each side. The box has a lock on…
The Thacher’s Calculating Instrument is a cylindrical slide rule which was patented by Edwin Thacher, C.E. on the first of November, 1881. The given instrument…
This 318 page book has a rust-coloured cover. This book is in the memory of Prof. L.W. MacDonald, Head of Mathematics Department from 1911 to…
Two clip-on stands for Aristo slide rules to prevent from scratching of the back-side of Aristo slide rules. These stands seem to be made to…
This 10″ abacus is made of plastic, with a dark brown frame and brown coloured beads. It is a 1/4 abacus, meaning that there is…
A 5″ slide rule was contained in a soft leather case and is made of celluloid. The slide is grooved and the cursor is metal…
This 16 cm slide rule is in the form of a plastic envelope (resembling a stock) with windows, within which a slide plastic sheet with…
This “calculator” is made of a plastic cover (resembling a stock) and a cardboard piece with numbers (such as a slide). This calculator has the…
A 5″ slide rule with a celluloid stock and slide of xylonite or ivorite. It is a Mannheim type of slide rule with scales only…