Abstract

In this paper Galileo’s we seek to follow Galileo’s mind as he constructs the principle of the complete isochronism of the pendulum from experimental observations and theoretical demonstrations. Our conclusion will be that the principle came from experiments with relatively small angle pendulums, coupled with a „leap“ from free fall along circular chords and ideas about the natural frequencies of physical systems. The pendulum experiments of the First and Fourth Day were, in all probability, never performed. The results claimes were simply illustrations of the isochronism principle.