This is a Jordan sunshine recorder made by the firm Henry J Green in Brooklyn, New York.  Its shown in the 1915 Henry J Green catalog and is listed in their 1892 catalog but with no drawing or photo.  Invented by J B Jordan around 1885, it uses photo-sensitive paper placed inside the 5 inch diameter drum to record the duration of sunlight.  Blueprint paper was usually used, it only required soaking in water to develop it.  The device is made of brass and was oriented with the front side facing south (in the Northern Hemisphere).  Pinholes on each side of the device allow a beam of light to burn a line in the paper as the earth rotates, so that the length of the line corresponds to the duration of sunlight.  The pinholes on this model can be moved with a slide so that 7 days of recording (7 lines) could be made without changing the paper.  The angle of the drum is adjusted to correspond to the latitude of the location, it is adjustable from zero to 45 degrees.

The US Weather Bureau used a modified form of Jordan sunshine recorder from about 1888 to 1897.  The US Weather Bureau version could record 31 days observations without changing the paper.  A disadvantage of this type was that the results were not available until the end of the month.  It was replaced in USWB service with the Marvin electrical sunshine recorder which allowed remote recording and instantaneous reading.

Go to Henry J Green catalog page.

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