Feature

Average Sleep Ration 25 Years

Comets and Meteors May Surround Stars

Helpfulness among Animals

Physical Science in the XVIIth Century

Chemist Makes Synthetic Sugar

Back Matter

Wild West Days in Siberia

Noguchi’s Lead Still Followed

First Glances at New Books

Million-Volt “Cosmic” Rays

Sphynxes Discovered

Classics of Science: Theory of Strata