RecordProportional compasses< 1 of 1 > Back probably made in London
Proportional compassesThis pair of proportional compasses were made around 1800, probably by Thomas Jones, a scientific instrument maker based at Charing Cross in London. The proportional compasses are dividers capable of several operations. The compasses can move about on a sliding pivot, altering the ratio between the long points at one end and the short ones at the other. This side has scales allowing the area and volumes of two-dimensional diagrams to be calculated. Proportional compasses were used in practical mathematics, particularly in skilled trades such as surveying and navigation, to calculate dimensions when transferring drawings either when enlarging or reducing. Record detailsTo search on related items, click any linked text below.
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