A cased set of pearwood drawing radii curves by Stanley of London, in a mahogany case. Circa 1900.
Width: 50 cm.
Depth: 20 cm.
Height: 10.5 cm.
See: Mathematical Drawing and Measuring Instruments: Their Construction, Uses, Qualities, Selection, Preservation, and Suggestions for Improvements, with Hints Upon Drawing, Colouring, Calculating, Sun Printing, Lettering, &c. by William Ford Stanley. E. & F.N. Spon, London. 1900. Chapter XXV, pages 222 – 227.