Front matter
Reading edition
SIGNALLING ACROSS SPACE WITHOUT WIRES.
BEING A DESCRIPTION OF
THE WORK OF HERTZ & HIS SUCCESSORS.
BY
PROF. OLIVER J. LODGE, F.R.S.
THIRD EDITION, With Additional Remarks concerning the Application to Telegraphy, and Later Developments.
LONDON: “THE ELECTRICIAN” PRINTING AND PUBLISHING COMPANY, LIMITED, Salisbury Court, Fleet Street.
Copyright.
Works by Dr. O. J. LODGE.
Lightning Conductors and Lightning Guards. A Complete Treatise on the subject of Electric Discharges in general.
Pioneers of Science. A popular Illustrated History of the Early Astronomers and their Work up to Recent Times.
Modern Views of Electricity.
Elementary Mechanics.
Protection of Buildings from Lightning. Mann Lectures to the Society of Arts, 1888.
Secondary Batteries and the Electrical Storage of Energy. Cantor Lectures to the Society of Arts, 1883.
TABLE OF CONTENTS.
(The lines in italics which look like headings of paragraphs are really statements about experiments which were at that place shown.)
1. Royal Institution Lecture on the Work
of Hertz and some of his Successors:— PAGES
Biographical Introduction 1
Elementary Explanation about Electrical Radiation
and Absorption and the Effect of Syntony 3-8
Syntonic Leyden Jar Experiment 6, 21
Side Observations on the Effect of Light
on Electric Discharge 9-12
Various Detectors of Radiation 13-23
Physiological Non-Effect of Sufficiently Rapid Alternations 17
Boltzmann Gap Detector—the Precursor of the Coherer 18
Branly’s Observations (see also Appendix, page 95) 20
Early Form of Coherer and of Branly Filings Tube 21-23
Early Signalling over 40 or 60 yards 24-25
Use of Telephone as Receiver 26
Experiments showing Syntony 27-28
Hypothesis concerning the Nature of Vision 29-31
Summary of Various Detectors of Radiation 30
Radiation Detected from extremely Weak Sparks, and by
very compact Receiver with Collecting Wire 32-34
Vacuum Filings Tube 34
Effect of Metallic Enclosure 35-38
Experiments on Reflection, Refraction, and Polarisation
of Radiation 39-42
Note about Electric Waves on Wires 43
2. Application of Hertz Waves and Coherer
Signalling to Telegraphy 45-48
Coherer Behaviour and Tommasina’s Experiment 49
Single-Point Coherer 55
General Remarks about Patent Law 50
Attempts at Syntonic Telegraphy 52-60
Syntonic Radiators and Receivers 51-56
3. Details of other Telegraphic Developments:—
Popoff’s 1895 Demonstration 60-62
Slaby’s Overland Experiments 63-66
Marconi’s Recent Demonstration 66-72
4. A History of the Coherer Principle 73-87
Professor Hughes’ Early Observations
before Hertz or Branly 88-94
Work of Monsieur Branly 95-108
5. Communications with respect to Coherer
Phenomena on a Large Scale:—
Professor Elihu Thomson 109
Dr. Morton 111
6. Photo-Electric Researches of Drs. Elster
and Geitel 115-126
7. Photo-Electric Researches of Professor Righi 127