Pendulum period is independent of the bob’s mass even when mass differs a hundredfold

Evidence

I took two balls, one of lead and one of cork, the former more than a hundred times heavier than the latter, and suspended them by means of two equal fine threads, each four or five cubits long. Pulling each ball aside from the perpendicular, I let them go at the same instant, and they, falling along the circumferences of circles having these equal strings for semi-diameters, passed beyond the perpendicular and returned along the same path. This free vibration repeated a hundred times showed clearly that the heavy body maintains so nearly the period of the light body that neither in a hundred swings nor even in a thousand will the former anticipate the latter by as much as a single moment, so perfectly do they keep in step. — Eric J. Heller, Why You Hear What You Hear- An…, 289

Categorization

• CANDY: Galileo’s lead-versus-cork pendulum demonstration is a wonderful elevator anecdote about early experimental method — a heavy ball and a light one swinging in perfect step.
• corroborated: 2 independent passages support this claim — Eric J. Heller, Why You Hear What You Hear- An…, 289