A BRIEF HISTORICAL SKETCH.
Early Records
Practical beginning of the Art—The London Pneumatic Telegraph
The Siemens Circuit System
Recent Improvements in the London System
An Underground Pneumatic Railway for Transportation of Mail
The Berlin Pneumatic Telegraph
The Paris Pneumatic Telegraph
The Pneumatic Telegraph of other Cities
Pneumatic Tubes in America
THE PNEUMATIC TRANSIT COMPANY AND THE FIRST PNEUMATIC TUBES FOR THE TRANSPORTATION OF UNITED STATES MAIL.
Organization
Aim and Object of the Company
The Clay-Lieb Patents
Franchises and First Government Contract
Search for Tubes
Method of Manufacturing Tubes
Laying and Opening the Tubes for Traffic
Description of the Tubes, Method of Laying, etc.
The Air-Compressor—Method of Circulating the Air
Terminal Apparatus
The Sender
Sub-Post-Office Receiver
Main Post-Office Receiver
The Carrier
Operation of the Tubes
Benefits of the System
THE SYSTEM AND APPARATUS OF THE BATCHELLER PNEUMATIC TUBE COMPANY.
General Arrangement and Adaptability of the System
The Size of Tubes
System of very Large Tubes
General Arrangement of Apparatus in the Stations—Two-Station, Two-Compressor Line
Two-Station, One-Compressor Line
Three- to Eight-Station Line
Sending Apparatus
Sending Time-Lock
Intermediate Station Time-Lock
Electro-Pneumatic Circuit-Closer
The Open Receiver
The Closed Receiver
The Intermediate Station Receiving and Transfer Apparatus
Carriers
Air Supply
Fans
Blowers
Air Compressors
The Tube, Line Construction, etc.
FACTS AND GENERAL INFORMATION RELATING TO PNEUMATIC TUBES.
Definitions
Intermittent and Constant Air-Current
Laws Governing the Flow of Air in Long Tubes
Law of Pressure
Uses of Pressure Curves
Law of Velocity
Characteristics of the Velocity Curve
Uses of Velocity Curves
Quantity of Air Used
Temperature of the Air
Horse-Power
Efficiency
Pressure and Exhaust Systems
Laws expressed in Mathematical FormulÆ
Moisture in the Tubes
Location of Obstructions in Tubes
