[Boatanchors] Dc Voltmeter Calibration

[Gary Peterson]

“I have in my curio of parts an unmounted device that consist of two 
connected sealed glass tubes, pointed on the ends and with a red and a 
black wire coming out of the opposite bases...When measured at the wire ends it consistently gives 1.0169 VDC...It measures the same year after year.  It appears to 
be a chemically energized lab grade voltage standard....Would be curious if anyone knows how it works.
Ray, W4BYG”

It is probably a Weston cell.  Weston cells were used as laboratory voltage standards when I took a course in chemical instrumentation, many decades ago.  Never put anything but a very high resistance load on it, or it will be permanently damaged.  It may also contain mercury and cadmium compounds.  If ever broken, clean up with care!  Google Weston cell for details.

Gary, K-zero-CX