Questions about the cartesian diver

• What are the advantages of the Cartesian diver?

      A: You can sink and float with a Cartesian diver, while submarines alone, are buoyant.

• How come Cartesian divers are called Cartesian divers?
• What uses Cartesian divers?

      A: Well, sometimes divers use it, but submarines always use it.

• What is a Cartesian diver?

      A: Read this blog and find out!

• Why bother make a whole blog about Cartesian divers?

History of the Cartesian Diver (most of it is copy and pasted)

The Cartesian diver was first described in writing in 1684, by Galileo's student, Raffaello. The term Cartesian, is thought to be from the last name of René Descartes, a French scientist, mathematician, and philosopher. Descartes was famous for saying, “I think, therefore I am”. Raffaelo Maggiotti, who is given credit for first describing the Cartesian diver or devil in writing (Rose, 1970). In a short pamphlet Maggiotti (1648, reprinted in Targioni-Tozzetti, Giovanni , 1780) speaks of the device as "my invention" ("L'invention mia non consiste nel caldo, o ned freddo; ma nella Renitenza all Compressione "). The diver has been falsely ascribed to Descartes (Damerow, 1994). The French do not refer to the diver as Cartesian but rather as ludion, a word derived from the Latin meaning actor, jester, wandering entertainer (Feral, 1994). URL 

http://www.ed.uiuc.edu/courses/CI241-science-Sp95/resources/philoToy/philoToy.html