Feature

Petty Gambling Costs U. S. $3,500,000,000 a Year

Bones, Turtle Shells Make Attractive Collection

Front Matter

School Books Not Likely to Carry Disease Germs

Plants Can Hinder or Help Each Other

Electrons, Corn, Bible Story, Figure in Smithsonian Report

New Midget Arc Lamp Rivals Sun in Brightness

In Science Fields

Mental Stock Market of Intelligence Explained

[Photograph]: Dollars from Heaven

First Glances at New Books

Gold-Plated Silk Shown to British Scientists