Campbell Stokes Sunshine Recorder
A Campbell Stokes Sunshine Recorder is a device used by meteorologists to record the actual duration of sunshine. It works by using the optically pure glass ball as a magnifying glass and burning a paper strip. As the sun arcs across the sky it causes the magnifying glass to burn a horizontal line on the paper strip. If the day is in and out of clouds, it burns a series of dots. You may well remember when you were outside and trying to burn something with your magnifying glass, it would not work when the sun was behind a cloud. This sunshine recorder works the same way. The sun has to be out and clear to put a burn mark or line on the strip. From the burn marks you can accurately determine the duration of sunshine for a day. A person would have to change the strip daily, unless it was cloudy the entire day. |