File:Masters of space- Morse and the telegraph; Thompson and the cable; Bell and the telephone; Marconi and the wireless telegraph; Carty and the wireless telephone; (1917) (14756079935).jpg

Identifier: mastersofspacemo00towe (find matches)
Title: Masters of space: Morse and the telegraph; Thompson and the cable; Bell and the telephone; Marconi and the wireless telegraph; Carty and the wireless telephone;
Year: 1917 (1910s)
Authors: Towers, Walter Kellogg, 1888-
Subjects: Morse, Samuel Finley Breese, 1791-1872 Kelvin, William Thomson, Baron, 1824-1907 Bell, Alexander Graham, 1847-1922 Marconi, Guglielmo, marchese, 1874-1937 Carty, John J. (John Joseph), 1861-1932 Telegraph Telegraph, Wireless Telephone Radio
Publisher: New York, London, Harper & brothers
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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blished, but the newsnever came. Finally he concluded that others,despite their greater opportunities, had notbeen so far-seeing as he had thought. Marconi attacked the problem himself withthe dogged persistence and the studious careso characteristic of him. He began his experi-ments upon his fathers farm, the elder Mar-coni encouraging the youth and providinghim with funds with which to purchase ap-paratus. He set up poles at the oppositesides of the garden and on them mounted thesimple sending and receiving instrumentswhich were then available, using plates of tinfor his aerials. He set up a simple spark-gap,as had Hertz, and used a receiving devicelittle more elaborate. A Morse telegraph-keywas placed in circuit with the spark-gap.When the key was held down for a longerperiod a long spark passed between the brassknobs of the spark-gap and a dash was thustransmitted. When the key was depressedfor a shorter period a dot in the Morse codewas sent forth. After much work and adjust- 202
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Copyright oy Brown Brothers. GUGLIEI.MO MARCONIPhotographed in uniform as an officer of the Italian army AN ITALIAN BOYS WORK ment Marconi was able to send a messageacross the garden. Others had accomplishedthis for similar distances, but they lackedMarconis imagination and persistence, andfailed to carry their experiments further. Tothe young Irish-Italian this was but a start-ing-point. Marconi quickly found that the receiverwas the least effective part of the existingapparatus. The waves spread in all direc-tions from the sending station and becomefeebler and feebler as the distance increases.To make wireless telegraphy effective overany considerable distance a highly efficientand extremely sensitive receiving device isnecessary. Some special means of detectingthe feeble currents was necessary. The co-herer was the solution. As early as 1870 aMr. S. A. Varley, an Englishman, had dis-covered that when he endeavored to send acurrent through a mass of carbon granulesthe tiny particles

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