Fig. 25 Fig. 26
Although many mathematical instruments of the Renaissance sought to combine a range of observational and calculating functions in one device, few (if any) achieved the selfconscious universality of the 'military proteus'. The name was deliberately chosen to highlight the instrument's capacity for transformation into a wide variety of configurations.
The first of the volume's three books deals with the construction of the instrument and its transformation into other instruments such as the 'radio latino' (catalogue nos 59 and 60). The second and third books embrace the various contexts in which the 'proteo' can be used, ranging across perspective, architecture, cartography, sculpture, fortification, typography, surveying, mensuration, astronomy, dialling and navigation.
As befits an instrument which was designed in the form of a dagger, there are also military uses of the 'proteo'. It is shown acting as a gunner's quadrant, and was intended to provide assistance both in ordering troops in formation and in setting out a military encampment. With the appropriate scales, it could also be used as a gunner's gauge. Further material on gunnery appears in a discussion of the design of various artillery pieces. The author, who published his Nautica mediterranea (1602) on navigation and ship-building under the name Bartolomeo Crescentio, displays his naval interests by mentioning the stone-throwing perrier guns used on board Venetian galleys.
This copy of the book is missing its title page and dedication.