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The Ballard Pavement

Experiments on the Head of a Guillotined Patient

Light and Vision--More Especially How Light is Converted Into Thought

By H. Knapp

A Trip Over the Central Pacific Railroad

Boring Insects

Improved Packing Steam Drying Cylinders on Paper Machines

Submerged Buoys as a Basis for Structures in Deep Water

Editorial Summary- April 23, 1970

Kay's Patent Reversible Slide Valve and Swing Grate

Stockwell's Improved Combination Tool

An Anglo-American Turkish Bath

Steam Boiler Inspection

Principle of the Lever

Shut Your Mouth

The West Side Elevated Railway

The Paris Observatory

Comparison of Turbines with other Water Wheels

Where and How Corks are Cut

Answers to Correspondents- April 23, 1870

Recent American and Foreign Patents- April 23, 1870

Official List of Patents- April 23, 1870

United States Supreme Court

H. S. Patent Office- April 23, 1870


  • Letters

    Correspondence- April 23, 1970

  • Recommended

    New Books and Publications- April 23, 1970

  • Departments

    Business and Personal- April 23, 1870

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April 23, 1870