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Show Strange Telephone Wire. Whether wo shall ever be a'ble to see our friends at a Ubtanre, as we now talk with them, is something for the sclencu of the future to determine, de-termine, but If we ever Jo so it will doubtless be through the roytterbus connection between light, electricity and tbe element selenium. Selenium belongs to what Is known as the sulphur group of elements. ele-ments. It Is remarkable for the wonderful property by which its electrical conductivity varies according ac-cording to the amount of light falling fall-ing upon it. Just as the chemical relations re-lations of silver are alltreel by1 the same means. By this singular properly of selenium sele-nium Professor Bell was able to construct an optical telephone, and actually transmitted words and sentences bstween two tlistant points which were not connected in any way except by a beam cf light, which faithfully carried the vit rations ra-tions of his voice to a selenium disk, by which they were transformed into electric energy and reproduced in an ordinary tclcpho.ne. Youth's Ojmpanton. |