Giambattista Della Porta, an Italian natural philosopher, born in Naples about 1540, died there, Feb. 4,1615. He opened his house to a society of literary men called i segreti, whose meetings were finally prohibited by the court of Rome on the supposition that magic and other unlawful secrets were discussed at them. He travelled extensively over Europe, liberally aiding the establishment of private schools for the study of particular sciences, and of public academies. Late in life he wrote dramas, which are now forgotten. His investigations, though frequently absurd, have proved of great value. The theory of light is much indebted to his labors, and he was the inventor of the camera obscura and other optical instruments, including, it was formerly supposed, the telescope. He was a voluminous writer on a great variety of subjects, including natural magic, the art of secret writing, human physiognomy, landscape gardening, optics, curvilinear geometry, chemistry, meteorology, etc. His chief work is De Humana Physiognomia (Sorrento, 1586; Italian translation by himself, fol., Naples, 1598).