摘要 |
An arrangement for determining the density of natural fog in the atmosphere in which a spark lamp serving also as a flashing beacon projects a beam of light composed of consecutive pulses through the fog laden atmosphere so as to scatter part of the light to thus form consecutive pulses of scattered light in a defined region of the path of the light beam, the intensity of which is proportional to the density of the fog in this region, and in which light pulse receiver means are constructed and arranged relative to said region so as to receive only the scattered light pulses which are measured by the receiver means to thereby indicate the density of fog in the aforementioned region.
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