Della Porta founded the Ostiosi (Men of Leisure) an early scientific society, a condition of membership being to demonstrate a new discovery in the natural sciences. The Academia Secretorum Naturae was suspected of dabbling in the Occult and Della Porta was summoned to Rome by Pope Paul V. The Society was closed down by the Inquisition but Della Porta defended and justified his search for truth in nature. He was cautioned and allowed to continue his studies of investigating nature's properties.
In 1586 Della Porta published a work on Physiognomy which later influenced the Swiss Pastor Johann Kaspar Lavater (1741-1801). Della Porta wrote extensively upon a wide spectrum of subjects throughout his life - including an agricultural encyclopaedia entitled Villa, as well as works on Meteorology Optics and Astronomy.
His work Phytognomica lists plants according to their geographical location. In a later edition of his Natural Magic, Della Porta described a Camera Obscura with a convex lens; though he wasn't the inventor of this technical refinement, the popularity of his work helped spread knowledge of the device.
In later life Della Porta collected rare specimens from the natural world and grew exotic plants. His private Museum was visited by travellers and was one the earliest examples of Natural History Museuems. It inspired the Jesuit Athanasius Kircher to begin a similar collection in Rome. Della Porta also wrote fourteen prose comedies and two dramatic tragedies which became source material for several 17th century dramatists. Della Porta's works are well-represented in the Library of Sir Thomas Browne by no less than six titles.
Works
Natural Magic 1558 expanded to 20 books 1589. English translation 1658 Available online at [[1]
De furtivis Literarum Notis((1563) On secret codes and Cryptography
Villa (1583-92) An agricultural encyclopaedia
De humana physiognomia (1586) On Physiognomy
De refractione optices (1589) On Optics
De aeris transmutanionbus (1609) On Meteorology
De distillatione (1610) Della Porta's chemical experiments and observations.