Apparatus for Warning a Ship at Sea of its Nearness to Large Objects Wholly or Partly under Water.

摘要

11,125. Richardson, L. F. May 10. Reflectors, sound.-A trumpet or parabolic reflector for subaqueous use is made either with walls of a thickness approaching one quarter of the wave-length of the sound used, or else with double walls enclosing an air layer which effects most of the reflexton, the inner wall being made thin to keep the waves reflected from its two surfaces approximately in phase.