Features
The Manufacture of Fire Bricks
Chemical News
Something about Silver
The Guava
What are Condiments?
Improved Implement for Drawing Nails
Natural History--The Great Auk
The Yosemite Valley
Portable Laughing Gas
Improved Coal-Breaking Machine
Rapid Telegraphy
An Invisible Chain and a Silent Conflict
The Darien Canal--Will it Pay to Build it?
The Wind Month
Economy in the Use of Time
How Fire Bricks are Made
Butter and Its Adulterations
The Study of Alloys
U. S. Patent Office
Recent American and Foreign Patents- April 2, 1870
Answers to Correspondents- April 2, 1870
Official List of Patents- April 2, 1870
Departments
- Letters
Correspondence- April 2, 1870
- Reviews
New Books and Publications- April 2, 1870
- Departments
Business and Personal- April 2, 1870
