page_title: Giambattista della Porta
section_title: Scientific disciplines
hierarchical_section_title: Giambattista della Porta / Scientific disciplines
caption_attribution_description: English: De humana physiognomonia libri IIII (1586) by Giambattista della Porta, page 19.
context_page_description: Giambattista della Porta, also known as Giovanni Battista Della Porta, was an Italian scholar, polymath and playwright who lived in Naples at the time of the Scientific Revolution and Reformation.
  Giambattista della Porta spent the majority of his life on scientific endeavors. He benefited from an informal education of tutors and visits from renowned scholars. His most famous work, first published in 1558, is entitled Magiae Naturalis. In this book he covered a variety of the subjects he had investigated, including occult philosophy, astrology, alchemy, mathematics, meteorology, and natural philosophy. He was also referred to as "professor of secrets".
context_section_description: In 1563, della Porta published De Furtivis Literarum Notis, a work about cryptography. In it he described the first known digraphic substitution cipher. Charles J. Mendelsohn commented:
  He was, in my opinion, the outstanding cryptographer of the Renaissance. Some unknown who worked in a hidden room behind closed doors may possibly have surpassed him in general grasp of the subject, but among those whose work can be studied he towers like a giant.
  Della Porta invented a method which allowed him to write secret messages on the inside of eggs. During the Spanish Inquisition, some of his friends were imprisoned. At the gate of the prison, everything was checked except for eggs. Della Porta wrote messages on the egg shell using a mixture made of plant pigments and alum. The ink penetrated the egg shell which is semi-porous. When the egg shell was dry, he boiled the egg in hot water and the ink on the outside of the egg was washed away. When the recipient in prison peeled off the shell, the message was revealed once again on the egg white.
  In 1586 della Porta published a work on physiognomy, De humana physiognomonia libri IIII (1586). This influenced the Swiss eighteenth-century pastor Johann Kaspar Lavater as well as the 19th century criminologist Cesare Lombroso. Della Porta wrote extensively on a wide spectrum of subjects throughout his life – for instance, an agricultural encyclopedia entitled "Villa" as well as works on meteorology, optics, and astronomy.
  In 1589, on the eve of the early modern Scientific Revolution, della Porta became the first person to attack in print, on experimental grounds, the ancient assertion that garlic could disempower magnets. This was an early example of the authority of early authors being replaced by experiment as the backing for a scientific assertion. Della Porta's conclusion was confirmed experimentally by Thomas Browne, among others.
  In later life, della Porta collected rare specimens and grew exotic plants. His work Phytognomonica lists plants according to their geographical location. In Phytognomonica the first observation of fungal spores is recorded, making him a pioneer of mycology.
  His private museum was visited by travelers and was one of the earliest examples of natural history museums. It inspired the Jesuit Athanasius Kircher to begin a similar, even more renowned, collection in Rome.
caption: From De humana physiognomonia, 1586
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