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creased the number of known planets, which
was then only six, including the earth.
On March 13th, 1781, Sir William Her-
schel was, as usual, engaged on examining
some small stars, and, noticing that one of
them appeared to be larger than the fixed
stars, suspected that it might be a comet.
To test this he increased his magnifying power
from 227 to 460 and 932, finding that, un-
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