Miniature tide computer, Abacus H93 - keyring

Miniature mechanical tide computer - reproduction of a device from 1570 built by Humphrey Cole; the original is kept at the British Museum in London.
Diameter 50 mm, depth 6 mm, weight 60 g
Made of zinc alloy and brass, lacquered using a technique dating back several hundred years.
Gift packaging: beautiful gift box with insert

Abacus, a device for predicting the times of sea tides. The instrument consists of a fixed dial marked with degrees from 0 to 360, an hourly scale, and a wind rose. Two movable dials are mounted on it. One indicates the lunar month with a 1-30 scale, and the other has an indicator beneath which there is a moon shape that changes as the indicator is moved. The device takes into account the wind direction, the number of days since the new moon, and the current age of the moon, enabling the prediction of sea tides.

On the other side of the device there is a beautiful wind rose.

A wonderful gift for a sailor, fisherman, astronomer, or enthusiast of historic technology.

User manual in English, French, Italian, and Spanish.

Product of the Spanish company Hemisferium.

The set includes an attractive decorative box with an insert on which the device rests.