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How to Study Steel

The Solid and Liquid States of Steel, and Need for Carefully Studying Each

By Cosmo Johns

Flower Camouflage

Peculiarities of Some Wild Flowers of Southern California

By Francis M. Fultz

Acquired Radio-Activity

Forty Years' Experiments with X-Rays, Cathode Rays, and Radium on Various Minerals

By William Crookes


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    July 05, 1919

    See the World from a Different Perspective

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