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formations, and extending over fully half
the lunar disc, like the star-shaped cracks
made on a sheet of ice by a blow. Similar
cracks radiate from other large craters. It
must be mentioned that these white rays
are well seen only in full light of the sun
at full moon, just as the white snow in the
crevasses of a glacier is seen bright from a
distance only when the sun is high, and dis-
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