This large Loga cylindrical slide rule consists of an aluminum frame supporting a horizontal rotating paper covered drum marked with 60 logarithmic C and D scales that are 20.5" long and run from 1,000 to 10,000. Each scale repeats part of the previous scale, so the instrument is approximately equivalent to a linear slide rule 50 feet (or 15m) long. A slotted cylindrical sleeve that is 13" long fits over the drum. It slides back and forth.

The Swiss firm of Heinrich Daemen-Schmid manufactured cylindrical Loga-Calculators between 1900 and 1935. They were used for calculations such as currency and mathematics.

Free post within New Zealand.

Overseas buyers please apply for shipping rates.