This is a UK Met Office pattern Mk II Gold Visibility Meter. It was first described in 1939 by Ernest Gold. I believe this example is from 1944. It uses a neutral density optical wedge which is slid into and out of the instrument to determine the point at which a distant light of known luminosity is just obscured. It is calibrated in nebules, an early British unit of visibility measurement. It was primarily used for airport visibility range measurement, primarily at nighttime.

The Gold meter had a relatively short operational life. It was criticized for being too subjective based on the different users. It is shown in the 1948 Casella catalog (available on this website) but not in the 1958 catalog. This example was found in Argentina.

​It measures 10.5 inches long contracted and 18 inches long with the slide fully extended. It is 3 inches tall and weighs 1.2 pounds.

Go to Casella Catalog Page.

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