Galileo's Lamp and an Observation on Swing of Pendulum

A story of Galileo's discovery of the isochronism of pendulum is bliefly reviewed. This discovery was made as Galileo saw the swing of a lamp in the cathedoral at Pisa in his young days （1583）. The present author had claimed that if Galileo had a stop-wateh in his hand at that time, he could not find the isochronism with ease, because the precise measurements may introduce the destruction of isochronism. And then, the present author carried out an experiment of pen-dulum in his study at his home, not at the school laboratory. However, it is rather easy to induce the isochronism from the observation thus performed. As a matter of fact, the swings are sooner damped and become to the moderate oscillation with small angle, ∂（=sin∂）. A comment is made on such a damped osccillation. And also, an appendix is given to the mathematical formulae enployed in his previous paper （1986）.