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Updated: August 28, 2026
The apparatus in which the exposures are made consists of a box a little over a meter in length, closed at the top by a board, in which is a circular aperture 15'8 cm. in diameter. Over this board may be placed a cover, in the center of which is a hole 0.05 cm. in diameter, which therefore lets through 0.00001 as much light as the full aperture.
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