Fig. 104

The ordering of soldiers in regular formations was a frequent topic of mathematical and military discussion. It was regularly included in expositions of the use of particular instruments, for example the 'military proteus' (catalogue no. 12). It also came within the bounds of William Oughtred's account of the manifold calculating uses of his 'circles of proportion'. The instrument consisted of a series of concentric logarithmic scales operated with rotating indices, and was in effect a form of slide rule. Oughtred provided some numerical examples on the calculation of troop formations amongst material that dealt with arithmetic, geometrical problems of plane and solid measurement, gauging, astronomy, and trigonometry. He pretended to no great military expertise but included his treatment principally as an exercise in the use of his instrument.

This copy of Oughtred's text has, as well as the book's title, an additional stamped inscription on the spine: 'CORRECT BY HIS OWN HAND'. The annotations do indeed appear to be by the author, since they record many emendations of which some (but not all) were featured in later editions of the book.