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RADIOMETER, CROOKE'S, DOUBLE
(0173) |
Similar to RADIOMETER, CROOKE'S, SINGLE in construction, but with one additional bulb mounted vertically above the first one giving a total of two bulbs with two independent sets of mica vanes. Both the vanes have black painted and bright sides configured opposite, so that their exposure to sunlight or sufficiently bright incandescent light source causes them to rotate in opposite directions. |
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