Download PDF, EPUB, Kindle Proceedings of the American Association for the Advancement of Science Volume 29, No. 1
Download PDF, EPUB, Kindle Proceedings of the American Association for the Advancement of Science Volume 29, No. 1
Proceedings of the American Association for the Advancement of Science Volume 29, No. 1 by American Association for Science
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Author: American Association for Science
Number of Pages: 156 pages
Published Date: 01 May 2012
Publisher: Rarebooksclub.com
Publication Country: Miami Fl, United States
Language: English
ISBN: 9781236173515
Download Link: Proceedings of the American Association for the Advancement of Science Volume 29, No. 1
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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1881 Excerpt: ... great in sunlight as it was in the dark. In Werner Siemens'17 experiments special arrangements were made for reducing the resistance of the selenium. For this purpose two fine platinum wires were coiled into a double flat spiral and were laid upon a plate of mica, so that they did not come into contact with one another. A drop of melted selenium was then placed upon the platinum wire arrangement, and a second sheet of mica was pressed upon the selenium so as to cause it to spread out and fill the spaces between the wires. Each cell was about the size of a silver dime. The cells were then placed in a parafflne bath and annealed. Siemens devised other arrangements of apparatus for reducing the resistance. In the form known as "Siemens' Grating," the two wires, instead of being coiled together, were arranged in zigzag shape, forming a sort of platinum gridiron. This was treated in the same way as the spiral arrangement. Another form of cell consisted of a sort of lattice-work or basketwork of platinum wires arranged upon a perforated mica plate, the wires interlacing with one another, and with the mica plate so as to make metallic contact only with alternate wires. He also found that iron and copper might be employed, instead of platinum. "Without dwelling further upon the researches of others I may say that all observations concerning the effect of light upon the conductivity of selenium had been made by means of the galvanometer, but it occurred to me that the telephone, from its extreme sensitiveness to electrical influences, might be substituted with advantage. Upon consideration of the subject, however, I saw that the experiments could not be conducted in the ordinary way, for the following reason: The law of audibility of the telephone is...
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Proceedings of the American Association for the Advancement of Science Volume 29, No. 1 by American Association for Science
Author: American Association for Science
Number of Pages: 156 pages
Published Date: 01 May 2012
Publisher: Rarebooksclub.com
Publication Country: Miami Fl, United States
Language: English
ISBN: 9781236173515
Download Link: Proceedings of the American Association for the Advancement of Science Volume 29, No. 1
---------------------------------------------------------------
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1881 Excerpt: ... great in sunlight as it was in the dark. In Werner Siemens'17 experiments special arrangements were made for reducing the resistance of the selenium. For this purpose two fine platinum wires were coiled into a double flat spiral and were laid upon a plate of mica, so that they did not come into contact with one another. A drop of melted selenium was then placed upon the platinum wire arrangement, and a second sheet of mica was pressed upon the selenium so as to cause it to spread out and fill the spaces between the wires. Each cell was about the size of a silver dime. The cells were then placed in a parafflne bath and annealed. Siemens devised other arrangements of apparatus for reducing the resistance. In the form known as "Siemens' Grating," the two wires, instead of being coiled together, were arranged in zigzag shape, forming a sort of platinum gridiron. This was treated in the same way as the spiral arrangement. Another form of cell consisted of a sort of lattice-work or basketwork of platinum wires arranged upon a perforated mica plate, the wires interlacing with one another, and with the mica plate so as to make metallic contact only with alternate wires. He also found that iron and copper might be employed, instead of platinum. "Without dwelling further upon the researches of others I may say that all observations concerning the effect of light upon the conductivity of selenium had been made by means of the galvanometer, but it occurred to me that the telephone, from its extreme sensitiveness to electrical influences, might be substituted with advantage. Upon consideration of the subject, however, I saw that the experiments could not be conducted in the ordinary way, for the following reason: The law of audibility of the telephone is...
Read online Proceedings of the American Association for the Advancement of Science Volume 29, No. 1 Buy and read online Proceedings of the American Association for the Advancement of Science Volume 29, No. 1 Download Proceedings of the American Association for the Advancement of Science Volume 29, No. 1 for pc, mac, kindle, readers Download to iPad/iPhone/iOS, B&N nook Proceedings of the American Association for the Advancement of Science Volume 29, No. 1 ebook, pdf, djvu, epub, mobi, fb2, zip, rar, torrent
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