Stephano degli Angeli (1623–1697) was a Catholic priest of the Order of Jesuate, the same as his teacher and colleague Bonaventura Cavalieri (1598–1647). Showing an early interest in mathematics and the concept of infinitesimals, Angeli studied and wrote on the behavior of various curves and physical applications of mathematics. In his *Accessionis ad Stereometriam et Mecanicam* (1662), he examined various solids and determined their centers of gravity.

The first page of text in *Accessionis*:

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