Word: selenium
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...like to hear ranchmen blame "alkali disease," because during the last century alkali disease afflicted the Indians inhabiting the same areas. Last week, when it could also report progress on a cure, the Department explained what was ailing the cattle. It was not alkali disease, said the Department, but selenium poisoning. Selenium is the light-sensitive substance used in photoelectric cells, and is closely related chemically to sulphur. From selenium compounds discovered in the soil of the affected districts, wheat and other plants absorb the poisonous element. The Department's investigators found that if sulphur-harmless alike to plant...
...built a large, efficient generator at Hartford, operated by mercury vapor instead of steam (TIME. July 8, 1929), is building another at Schenectady. The mercury boilers are dangerous because they might leak mercury, poison the workmen. A delicate mercury detector was in order. It is a yellow plaque of selenium sulfide. A few drops of mercury in a furnace through which pass more than 200,000 Ib. of flue gas an hour, said A. J. Nerad, blackens the yellow plaque. The degree of blackening indicates the amount of mercury present. A photo-electric cell measures the blackening, warns workmen...
...visagraph works as follows: slim beams of light are reflected from a printed page into a selenium cell which translates the blank and printed patches into various electrical frequencies. The currents operate electromagnets which drive pins against a sheet of aluminum. The aluminum progressively becomes embossed with letters as the master light roves across the original page. The blind thereby can feel the upcoming words almost as fast...
...presence of as little as one part of mercury in 20,000,000 parts of atmosphere. Before the poison is detected by symptoms of illness in drooping employes, a coating of yellow sulphide on a strip of paper gives the signal by turning black (the result of contact between selenium sulphide and mercury). The degree of blackness is photographed by shining a light through the strip of yellow sulphide. If the sulphide has turned dark, less light will penetrate; if black, no light will penetrate. This is recorded on an ammeter legible to every...
...score gentlemen who went were impressed deeply by the ingenuity of Mr. Baird's "optical lever," a series of whirling lenses mounted on discs, which break up an optical image into minute constituent parts. They were even more impressed by the Baird photo-electric cell, of the colloidal selenium type, which could capture and transmit the minute image parts at unprecedented speed. Last week, between sessions of the British Association, members sought out Inventor Baird in Leeds to see him manipulate his latest tele-visors, which are now so refined that they can "see things at night." Using infra...