(_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