No abstract

Underwater imaging of the air environment is described with particular attention given to the optical problems of nearhorizon viewing. These include severe chromatic aberration from transmission through the seawater wedge, the horizon distortion effect, and anisoplanatism resultingfrom the change of refractive aberrations in different areas of view. Various optical designs or schemes are presented that correct or relieve thefirst two optical problems. Strategies to minimize or attempt to view through the varying refraction ofthe surface are also suggested, and one is investigated.

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A Van de Graaff accelerator facility has been used as a supersensitive mass spectrograph in a search for free + %\e\ and + §|e| charged ions in helium gas. No such ions were found at a level of sensitivity better than 1 part in 3.9x io 14 He atoms. The mass ranges spanned were 0.13 to 7.5 amu for +^\e\ ions and 0.27 to 15.0 amu for + §H ions,

No abstract