This extraordinary manuscript, dedicated to the Duke of Joyeuse, gathers ideas on the nautical navigation, astronomy and cartography as well as extensive annotations, observations and records Devaulx himself as a sailor, hydrographer and cosmógrafo, creating an encyclopedic reference for sailors and a real gem maritimefor your real employers. In his manuscript, richly annotated and ornamented, Jacques Devaulx exposes the naval and cosmographic practices and discoveries of his time, and includes traditional maritime technologies such as astrolabes, methods of measuring the altitude of the Sun and stars and tables with the states of the tides diurnal, as well as nautical charts of the Atlantic Ocean.