Identifier: ourcountryitsres00hopk (find matches)
Title: Our country and its resources;
Year: 1917 (1910s)
Authors: Hopkins, Albert A. (Albert Allis), 1869-1939
Subjects: United States. (from old catalog)
Publisher: New York, Munn & co., inc.
Contributing Library: The Library of Congress
Digitizing Sponsor: Sloan Foundation

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of combiningthese into a wireless system, eachidea by itself was crude and hadto be systematically developed.These distances, covered with Mar-conis early apparatus, speak vol-umes for the rate of progress madeby him: 1895, 30, 100, and 2,400meters, or 1% miles: 1897, 14 miles;1898, 20 miles: 1899, 85 miles: 1900,well over 100 miles: 1001. trans-atlantic transmission of the letters in the Morse code, over a dis-tance of 2,200 miles. In the yearsthat followed, the progress madewas so rapid that long-distance com-munication has now become quitecommonplace. Radio telegraphy, as we know itto-day, is not the invention of anyone man. Not unlike all other greatinventions it represents the laborsof numerous investigators and in-ventors, many known to us and manymore unknown to us. Among thebetter known later-day contributorsto wireless telegraphy are Lodge.Muirhead. Salby. von Arco. Rraun.Fleming, Fessenden, DeForest. Stone,Shoemaker. Blondel, Artom, Pick-ard. von Repel. Poulsen, and Pierce.
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386 (ill! COUNTRY AND ITS RESOURCES HOW ELECTROMAGNETIC WAVES TEAVELTHROUGH SPACE it would be difficult to explainhow electromagnetic waxes, whicharc not susceptible to our senses,travel from a wireless transmitterto a receiver at the astounding rateof 186,300 miles per second, were itnot for the simple analogy offeredby a body of still water. Suppose a stone is thrown intoa quiet pool of water. It will benoticed that waves or ripples formin perfect circles around the spotwhere the stone struck the surface,spreading out in ever-widening cir-cles from the source. The ripplesnear the center are big and readilyseen, while those some distance awayare small and barely discernible,finally disappearing altogether, pro-vided the body of water is sufficient-ly large. In other words, the rip-ples are largest near the source ofdisturbance, but lose their strengthin a gradual decrease the fartherthey are removed from the source. Although according to appearancesthe waves or ripples appear to form

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