Editing Gerolamo Cardano (section)

==Other contributions==
{{more citations needed section|date=September 2017}}
[[File:Leone leoni (attr.), medaglia di girolamo cardano, verso con sogno di cardano, 1550-51.JPG|thumb|right|200px|"Oneiron" ("Dream"), reverse of the medallion of Cardano by [[Leone Leoni]], 1550–51]]
Cardano was a [[music theorist]] who studied music privately in Milan in his youth. He wrote two treatises on music, both of which were titled ''De Musica''. The first was published within his 1663 work ''Hieronymi Cardani Mediolanensis Opera Omnia''. It is of interest to scholars on the history of [[woodwind instruments]] because of its discussion of instruments from that family. The second treatise was published in 1574, and a copy of it is held in the [[Vatican Library]]. The work is valuable for studies in [[harmony]] for its discussion of the use of [[microtones]]. It is also of interest to scholars of [[historically informed performance]] practice for its details on 16th century performance. The later treatise of music ''Della natura de principii et regole musicali'' which has been attributed to Cardano by some, is according to ''[[The New Grove Dictionary of Music and Musicians]]'' most likely falsely attributed to Cardano and is by another writer. Cardano also dabbled in composing, writing the [[motet]] '' Beati estis'' which is scored for 12 voices and contains four overlapping [[canon (music)|canons]].<ref name="Grove">{{Cite encyclopedia|date= 2001|entry=Cardano, Girolamo [Cardan, Jerome; Cardanus, Hieronymous]|encyclopedia=Grove Music Online|publisher=[[Oxford University Press]] |doi=10.1093/gmo/9781561592630.article.04908|author=Clement A. Miller|title=Cardano, Girolamo }}</ref> 

Cardano's work with hypocycloids led him to [[Tusi couple#Later examples|Cardan's Movement]] or Cardan Gear mechanism, in which a pair of gears with the smaller being one-half the size of the larger gear is used to convert rotational motion to linear motion with greater efficiency and precision than a [[Scotch yoke]], for example.<ref>{{cite web|title=How does a Cardan gear mechanism work?|url=http://www.mekanizmalar.com/cardan_gear.html|publisher=Seyhan Ersoy|access-date=1 April 2015}}</ref> He is also credited with the invention of the Cardan suspension or [[gimbal]].

Cardano made several contributions to hydrodynamics and held that [[perpetual motion]] is impossible, except in celestial bodies. He published two encyclopedias of natural science which contain a wide variety of inventions, facts, and occult superstitions. He also introduced the [[Cardan grille]], a cryptographic writing tool, in 1550.

Significantly, in the history of [[education of the deaf]], he said that deaf people were capable of using their minds, argued for the importance of teaching them, and was one of the first to state that deaf people could learn to read and write without learning how to speak first. He was familiar with a report by [[Rudolph Agricola]] about a deaf-mute who had learned to write.

Cardano's medical writings included: a commentary on [[Mundinus]]' anatomy and of [[Galen]]'s medicine, along with the treaties ''Delle cause, dei segni e dei luoghi delle malattie'', ''Picciola terapeutica'', ''Degli abusi dei medici'' and ''Delle orine, libro quattro''.<ref>{{cite journal|first1=David Eugene|last1=Smith|author-link1=David Eugene Smith|title=Medicine and Mathematics in the Sixteenth Century|pmc=7927718|pmid= 33943138|journal=Ann Med Hist.|date=July 1, 1917|volume= 1|issue=2|pages=125–140|oclc=12650954}} (here cited p. 130).</ref>

Cardano has been credited with the invention of the so-called ''[[Cardano's Rings]]'', also called Chinese Rings, but it is very probable that they predate Cardano. The [[universal joint]], sometimes called ''Cardan joint'', was not described by Cardano.