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Articles101 articles archived since 1845

What is a Chemical Element?

Our Concept of the Chemical Element Modified by Study of Radio-Active Change

August 2, 1919 — Frederick Soddy

How Old is the World?

The Various Answers Offered to the Question by Different Schools of Science

April 19, 1919 — William Harvey McNairn

The Age of the Earth

A Discussion of Recent Evidence from Geology and Astronomy

January 18, 1919 — Harlow Shapley

The Periodic Law

A Review of Late Developments and a Revised Form of Mendelejeff's Table

January 15, 1916 — Saul Dushman

The Age of the Earth

A Defense of Lord Kelvin's Theory and Comment on the Same

September 18, 1915 — F. A. Lindemann

Sea-Salt and Geologic Time

A Discussion of Prof. Joly's Method of Determining the Age of the World

January 30, 1915 — H. S. Shelton

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