in Electrical Machines; The Leyden Jar; The Speed of Electricity; Sir William Watson's Theories; Miscellaneous Discoveries; Benjamin Franklin's Experiments; Atmospheric Electricity; Experiments in Europe with Atmospheric Electricity; Electrical Induction, Electroscopes; Other Discoveries in the Eighteenth Century

VOLTAIC ELECTRICITY, ELECTROCHEMISTRY, AND ELECTROMAGNETISM 34

Galvani's Frog Experiments; Volta and the Voltaic Pile; Evolution of the Battery and Discoveries with Electric Currents; Electromagnetism; Ampere; Arago, Biot and Savart; Faraday's Rotating Conductor and Magnet and Barlow's Wheel; Sturgeon's Electromagnet, Galvanometers; Ampere's and Ohm's Laws.

FARADAY AND HENRY 52

Faraday's Formative Years; Faraday Appointed to the Royal Institution; Electromagnetic Induction; Other Contributions by Faraday; Joseph Henry; Henry's First Excursions into Science; Henry Proposes the Electromagnetic Telegraph; Electromagnetic Induction; Self-Induction; Marriage and Professorship at Princeton; Electrical

Oscillations and Electromagnetic Waves; Other Researches; The

Smithsonian Institution.

DIRECT-CURRENT DYNAMOS AND MOTORS 71

Pixii's Machine; Nollet's Machines; Dynamos; Electric Motors.

IMPROVEMENTS IN BATTERIES AND ELECTROSTATIC MACHINES 77

The Daniell Cell; The Grove Cell; the Leclanche Cell; Other Batteries; Storage Batteries; Electrostatic Induction Machines.

ELECTRICAL INSTRUMENTS, LAWS, AND DEFINITIONS OF UNITS 85

Tangent Galvanometer; D'Arsonval Galvanometer; Wheatstone Bridge; Electrical and Magnetic Laws; Electrical and Magnetic Units.

THE ELECTRIC TELEGRAPH 95

Early Electromagnetic Telegraphs; Samuel F. B. Morse; Demonstration of the First Morse Telegraph; Partnership with Alfred Vail; U.S. Government Interested in Telegraph; Demonstrations of the Improved Morse Telegraph; Patent Applications; Submarine Cable; Congress Appropriates $30,000 for an Experimental Line; Construction of the Line; "What Hath God Wrought!"; Commercial Operation of the Telegraph; Construction of New Telegraph Lines; Western Union; Printing Telegraphs; Relays; Duplex and Multiplex Systems; Railway Telegraphs; The First Transcontinental Telegraph Line; Electrical Manufacturing.

THE ATLANTIC CABLE 115

Early Submarine Cables; Newfoundland Cable; The Atlantic Cable; Cable Company Is Organized; Contracts for the Manufacture of Cable; The Cable Fleet; Loading and Testing the Cable; Laying the Cable; Project Postponed until the Following Year; Second Attempt; Cable Is Spliced in Mid-Ocean; Insulation Breaks Down; The Second Cable; Most of the Cable Is Laid Successfully Before It Breaks; The Third Cable; The Siphon Recorder.

THE TELEPHONE 131

Bourseul and Reis; Alexander Graham Bell; The Bell Family Moves to Canada; Classes in Boston; The Harmonie Telegraph; Boston University and George Sanders; Thomas A. Watson; The Phonautograph and the Reis Telephone; Meeting with Joseph Henry; Agreement with Sanders and Hubbard; Bell's Great Discovery; Despair; New Quarters; Telephone Patent Granted; The Telephone at the Centennial Exposition; Testing the Telephone; Western Union Refuses to Buy the Telephone; Bell Is Married; Organization of Telephone Companies; Infringement by the Western Union Telegraph Company; Bell Patent Upheld; Transmitters; Theodore N. Vail; Evolution of the Bell Companies; The Dial Telephone; Bell Laboratories and Western Electric Company; Other Telephone Systems.

ELECTRIC LIGHTING 152

Arc Lamps; Arc Lamp Mechanisms; Carbons; Manufacturers; Street Lighting; Enclosed Are Lamps; Flaming Arcs; Incandescent Electric Lights; Edison's Incandescent Lamp; Edison Electric Light Company; Menlo Park; The Search for Better Filament Materials; Improvements in Lamp Seals and in Dynamos; First Commercial Installations; Pearl Street, the First Central Station for Incandescent Lighting; Schenectady Works; Foreign Incandescent Light Installations; Improved Lamps; Other Types of Lamps; Metal Filament Lamps; Tube Lighting; Fluorescent Lamps; Lamp Efficiencies; Special-Purpose Lamps.

ALTERNATING CURRENTS 177

The Transformer; Induction Coils; Gaulard and Gibbs; Westinghouse Alternating-Current System; Alternating-Current Generators; Frequencies; AC-DC Conversion; Alternating-Current Motors; Niagara Falls Development; Transmission Lines; Frequency and Voltage Standards.

ELECTRIC TRACTION 190

Public Transportation; Rails and Railways; Street Railways; Electric Propulsion; Electrification of Street Railways; The Carbon Brush;

Rapid Conversion from Horsecars to Electric Propulsion; Suburban and Main Line Electrification; The Decline of Electric Street Railways.

ELECTROMAGNETIC WAVES, RADIO, FACSIMILE, AND TELEVISION 198

A Century of Progress; Hertz Discovers Electromagnetic Waves; Signaling without Wires; Guglielmo Marconi; First Radio Patent; Tuned Circuits; Continuous Waves; Detectors; The Edison Effect; The Fleming Valve; De Forest Audion; Amplification; Armstrong's Oscillator Tube; The Alexanderson High-Frequency Generator; Amateur Radio and Radio Broadcasting; Regulation of Radio; Federal Communications Commission; Frequency Allocations; Radio Receivers; Facsimile Transmission; Commercial Facsimile; Photoelectric Devices; Pictures by Cable; Television; The Scanning Disk and Mechanical Television; The Iconoscope; Improvements on the Iconoscope; Transmission by Radio Waves; Regulation of Television and Channel Allocations.

THE CROOKES TUBE, X RAYS, RADIOACTIVITY, STRUCTURE OF THE ATOM, ACCELERATORS AND ATOMIC RESEARCH 224

The Crookes Tube; Vacuum Tubes before Crookes; Sir William Crookes and His Experiments; Later Developments in Cathode Rays; X Rays; Radioactivity; Scattering of Electrons; Photoelectric Effect; Planck's Constant; Photoelectrons and Einstein's Equation; Hydrogen Spectra; Structure of the Atom; Heavier Atoms, Elliptical Orbits, and Spin; Theoretical and Experimental Physics of the 1920s; Other Subatomic Particles; The Electron Microscope; Radiation Detectors; Accelerators and Atomic Research.

MICROWAVES, RADAR, RADIO RELAY, COAXIAL CABLE, COMPUTERS 253

Microwaves; Radar; Early British Developments and Installations; American Wartime Research and Development; New Oscillators and Other Tubes; Types of Radar; Other Uses of Radar; Telephone Radio Relay; Frequency Band Allocations; Coaxial Cable; Computers; Computer Development; Digital and Analog Computer-; Electronic Computers; Memory Systems', Input and Output Systems; Numeration.

PLASMAS, MASERS, LASERS, FUEL CELLS, PIEZOELECTRIC CRYSTALS, TRANSISTORS 275 Plasmas; Masers and Lasers; Gas Lasers; Applications; Electrolytic and Electrochemical Phenomena; Piezoelectricity; Solid State Devices; Semiconductors; Transistors; The Transistor Industry.

ATOMIC ENERGY, GOVERNMENT RESEARCH, NUCLEAR FUSION 289

Atomic Energy; Nuclear Research for the United States Government; Los Alamos Laboratory and the Atomic Bomb; Atomic Energy Commission; Nuclear Power Plants; Nuclear Fusion; Whither.

BIBLIOGRAPHY 299