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Show Diving Bell of 200 Years Ago. It wns nearly 200 years ago that Kdmund Halley constructed what Is often referred to ns the first diving bell, although tho apparatus must havo been much like that which wns used In the presenco of Chnrlos V. Tho principle of tho diving boll Is simple. An Inverted Jar sunk In tho water retains air nt Its top, and if thero Is enough air men may llvo nnd brentho and work there, nnd keep dry. Dr. Halloy's diving bell wns ft largo wooden chamber, open at tho bottom and loaded there with lead to prevent It from turning In tho wntor. Pieces of glass set In tho roof furnished light. Air wns supplied by nn Ingenious method; for leaded casks full of nlr wero sent down, bung downward. Tipping Tip-ping tho barrel, water would rush Into It and drive out tho nlr to tho man In tho boll chnmbcr. At tho depth of thlrty-tlireo feet tho air Is compressed to half Its former bulk, and tho bell Is theroforo nt tho depth tilled full with water; and ns tho depth increnses, so do tho compression com-pression nnd tho prossure. Technical World Magazine. |
