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ours. He supposed them to be clouds. Scheiner[1]
said they were the indications of tumultuous
movements occasionally agitating the ocean
of liquid fire of which he supposed the sun
to be composed.
A. Wilson, of Glasgow, in 1769,[2] no-
ticed a movement of the umbra relative to
the penumbra in the transit of the spot over
the sun’s surface; exactly as if the spot were
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