Feature

Acid Stomach in Old Age May Be Index to Long Life

Mapping of Nation Speeded by Public Works Allotment

Weed Cultivated to Make Lawns

Nature Ramblings: Chalcis Fly

Scientists to Identify Unprofitable Lands

New U. S. Submarine’s Hull Joined Together by Welding

Tanks Fight Fires in California Woods

First Glances at New Books

Front Matter

Fast-Moving Positive Particles Produce New Kind of X-Rays

Exposition Visitors Examined for New Racial Type

Blast Furnace Gets Phosphorus Cheaply from Tennessee Rock