FIRST EDITION OF THE FIRST APPEARANCE IN ENGLISH OF HERTZ’S PAPER ON THE PROPAGATION OF ELECTRIC WAVES IN A WIRE. “This discovery and its demonstration led directly to radio communication, television and radar” (Dibner, Heralds of Science, 71). The most dramatic prediction to emerge from James Clerk Maxwell’s 1865 theory of electromagnetism was the idea of electromagnetic waves moving at the speed of light as well as the conclusion that light itself was just such a wave. Maxwell’s theory challenged experimental scientists to try to generate and detect electromagnetic radiation by using some type of electrical instrument. After its formulation, Maxwell’s electromagnetic theory remained a brilliant mathematical contribution, but one without any practical application because waves had not been generated experimentally.
Beginning in 1887, Heinrich Hertz, a brilliant German researcher, began a series of experiments that both confirmed the existence of electromagnetic waves and verified that they travel at the speed of light. Hertz built an oscillator made of polished brass knobs, each connected to an induction coil and separated by a tiny gap over which sparks could leap. “Hertz reasoned that, if Maxwell's predictions were correct, electromagnetic waves would be transmitted during each series of sparks. To confirm this, [he] made a simple receiver of looped wire. At the ends of the loop were small knobs separated by a tiny gap. The receiver was placed several yards from the oscillator.
“According to theory, if electromagnetic waves were spreading from the oscillator sparks, they would induce a current in the loop that would send sparks across the gap. This occurred when Hertz turned on the oscillator, producing the first transmission and reception of electromagnetic waves. Hertz also noted that electrical conductors reflect the waves and that they can be focused by concave reflectors. He found that nonconductors allow most of the waves to pass through” (Jones, Harvard CSCIE129). In other words, waves radiated from a transmitter circuit and were detected in a receiver circuit.
From this relatively simple device, Hertz was first to generate and detect electromagnetic waves in the laboratory. He understood that electrical circuits would have resonant frequencies just as do mechanical systems, and thus was able to demonstrate waves from a spark transmitter precisely of the same nature as predicted by Maxwell and of light waves (though here they were much longer, about 60 cm wavelength). "By inducing the waves to produce an electrical spark at a distance, with no apparent connection between the oscillator and the spark gap, and by moving the sparking apparatus so that the length of the spark varied, Hertz proved beyond question the passage of electric waves through space" (Printing and the Mind of Man, 377). Item #659
CONDITION & DETAILS: London: Taylor & Francis. (8.5 x 5.5 inches; 213 x 138mm). Complete. , viii, , 4. Fourteen plates and in-text illustrations throughout. Ex-libris bearing an armorial bookplate from St. John’s College on the front pastedown and a small stamp on the rear of the title page. Handsomely, solidly, and tightly bound in three quarter brown calf over marbled paper boards with minor scuffing Five gilt-ruled raised bands at the spine; gilt armorial devices in the compartments. Gilt-lettered red and black morocco spine labels. Bright and clean. Near fine condition.