DELLA PORTA, GIOVANNI BATTISTA (c. 1538 1615 ), Italian natural philosopher, was born of a noble and ancient family at Naples about the year 1538. He travelled extensively in Italy, France and Spain, and was still a youth when he published Magia naturalis, sive de miraculis rerum naturalium lib. IV. (1558), the first draft of his Magia naturalis, in 20 books, pub lished in 1589. He founded in Naples the Academia Secretorum Naturae, otherwise known as the Accademia dei Oziosi ; and in 1610 he became a member of the Accademia dei Lincei at Rome.
Porta is the author of a number of books on cryptography, physiology of plants, farming, gardening, optics, etc. He also wrote several Italian comedies. His most important work, the Magia naturalis, deals with a strange medley of subjects, includ ing the reproduction of animals, the transmutation of metals, pyrotechny, domestic economy, statics, hunting, the preparation of perfumes. Most of his work contains descriptions of experi ments which were never performed and is much exaggerated. The only portions of any great interest are the experiments on mag netism and the optical experiments which include a description of the camera obscura (q.v.).