The Popular Science Monthly, August, 1900

A snapshot of scientific thought at the turn of the twentieth century, this issue gathers essays and speeches that illuminate both the grand questions and the everyday tools of discovery. It opens with a presidential address to the American Association for the Advancement of Science, honoring a former leader while emphasizing the society’s role as a bridge between professional researchers and the broader public that supports and benefits from their work.

The centerpiece explores the timeless puzzle of the Earth’s age, tracing how scientists have tried to gauge deep time through geology, physics, and careful reasoning. Interwoven with this are fascinating reflections on the ancient devices we still use to mark moments—water clocks, hour‑glasses, and even the steady burn of a candle—showing how simple observations can lead to profound insights. Listeners will come away with a richer appreciation of the historical roots of modern science and the enduring curiosity that drives it.