| 摘要 |
In accordance with the present invention a viewing device for flotation bodies is provided which comprises a body having an interior defined by its side walls and at least one transparent end wall. In one embodiment using two transparent end walls, the transparent end walls define spaced-apart viewing ports, one port being normally above the surface of the water and the opposite port being below the surface of the water. The interior of the body is adapted to be substantially condensation free by evacuating the interior of the body and sealing the body in the evacuated condition or, more preferably, filling the body with a fluid to the exclusion of air so that condensation and air bubbles are thereby avoided. In a preferred embodiment the viewing device consists of a single piece body having a single transparent end wall.
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