Feature

Saw Replaces Explosives in Coal Mining

Front Matter

Reinforced Concrete: “A Classic Invention”

First Glances at New Books

New Inventions Make Possible More Accurate Time Keeping

Nature Ramblings: Too-Dominant Parents

Positive and Negative Electrons Apparently Produced in Pairs

[Photograph]: Poor Little Mastodon

Thousands of Animals Used Sponge as House

Prediction of Tidal Wave Forestalls Harbor Damage

Petroleum Said to Come from Garbage of Sea

First Chemical Evidence of Artificial Transmutation