Ciencia en el Barroco español: nuevas fuentes documentales de Jerónimo de Ayanz

Recently, a printed document of Jeronimo de Ayanz, acquired by the Biblioteca Nacional de Espana (the National Library of Spain), has revealed that this inventor was active until the very last days of his life and shows his interest in technology, research and science. The document, addressed to the Prince Emmanuel Philibert of Savoy, is one chapter of a book, of which no copies are known, that Ayanz had prepared in 1612 and that he probably wanted to publish with the support of the Prince. In this paper we present and comment this important text, where the author discusses central scientific subjects of his time such as the compulsory movement of the elements, the existence of vacuum, the possibility of perpetual motion, the sphere of fire and falling bodies.