Thomas Marquois was a Huguenot, living in London in the last quarter of the 18th century. Around 1778, he invented a set of parallel scales that greatly simplified military sketching in the field. The set consisted of two scale rules and a right-angle triangle.

Although Marquois sank into obscurity after his death in 1802, his scales did not and Marquois parallel scales are described in nearly every English book on mathematical instruments published during the nineteenth century. Many of the best-known mathematical and scientific instrument makers offered them. Numerous examples are found in tool sales and antique shops.

In this monograph, the author outlines Marquois's life, explains how the scales were used, who made them and several later improvements. It includes Marquois's own instructions for their use.

210 x 264mm 86 pp ISBN 978-0-947673-24-6

Prices including postage are

UK: £7.00

Europe: £10.50

Rest of World: £15.50

Please note that sales in the USA are from Astragal Press.