Here is seen an invisible speck of radium throwing out invisible atoms that sparkle into sight on a film. This stream of atoms will pour forth for 2500 years before the radium ceases to exist, thus showing the marvelous energy stored up in the smallest particle. These flying particles fall on the screen or film like hailstones splashing on the surface of water, and the splash is visible, while the radium itself and flying atoms are not. This is the nearest men have yet come to seeing an actual atom.

[Large photograph] (268 kB)

BOOK OF THE SCIENCES AND INVENTION

HISTORICAL DEVELOPMENT OF THE SCIENCES

[OUTLINES OF SCIENCE FOR SCHOOLS]

[PRACTICAL MATHEMATICS FOR DAILY USE]: Business and Industrial Arithmetic, Everyday Applications of Percentage, Weights and Measures, Mensuration and its Applications

[COMMERCIAL] AND INDUSTRIAL LAW