. Challenger; the life of a survey ship. Challenger; Hydrographic surveying. WORLD VOYAGE BEGINS 187 fathoms of water separating her from the ocean bed. To carry out such experiments a ship must be fitted with special apparatus. 6 TO 20 MILES ' SONO-RADIO BUOYS. xxxxxxxxxxxx X BASEMENT ROCK x XX xxxxxxxxxx A seismic refraction experiment, showing the paths by which various sound waves travel from explosion to the hydrophones A comparatively flat area of the ocean bed having been found, four sono radio buoys are laid about half a mile apart. Each buoy has a hydrophone slung beneath it in the wa
. Challenger; the life of a survey ship. Challenger; Hydrographic surveying. WORLD VOYAGE BEGINS 187 fathoms of water separating her from the ocean bed. To carry out such experiments a ship must be fitted with special apparatus. 6 TO 20 MILES ' SONO-RADIO BUOYS. xxxxxxxxxxxx X BASEMENT ROCK x XX xxxxxxxxxx A seismic refraction experiment, showing the paths by which various sound waves travel from explosion to the hydrophones A comparatively flat area of the ocean bed having been found, four sono radio buoys are laid about half a mile apart. Each buoy has a hydrophone slung beneath it in the water and within the buoy itself is a receiver and transmitting wireless set, with bat- teries. An aerial is carried on the buoy's mast. Having laid the buoys, the ship moves off to a distance of eight miles or so and fires a depth charge. This forms a source of sound which travels out in all directions in the sea. One path of sound travels horizontally through the water to the hydrophones below the buoys whence it returns to the ship as a radio signal. An accurate timing device in the ship records the time of the firing of the depth charge and the returning signal from the buoys. The speed of sound in sea water is known (^000 feet per second) so that a range of the buoys has now been found. Other paths of sound lead towards the sea-bed and then hori- zontally through the layer of sediment. As this sound passes 14. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Ritchie, G. S. (George Stephen), 1914-. New York, Abelard-Schuman
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Keywords: ., bookcentury1900, bookcollectio, booksubjecthydrographicsurveying
