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fine the path of comet 1556. After being
lost for 300 years, this drawing was recov-
ered by the prolonged efforts of Mr. Hind
and Professor Littrow in 1856.]
When Wells’s comet, in 1882, approached
very close indeed to the sun, the spectrum
changed to a mono-chromatic yellow colour,
due to sodium.
For a full account of the wonders of the
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