I imagined... it was possible... to establish by what means the circle could be squared, or... that it could... not, or... something would emerge... worthwhile. Arithmetica Infinitorum (1656)
This method of mine takes its beginnings where Cavalieri ends his Method of indivisibles. ...for as his was the Geometry of indivisibles, so I have chosen to call my method the Arithmetic of infinitesimals. Arithmetica Infinitorum (1656)