Page 641 - 89 history of astronomy_opt

the same spectrum.
˜
Other nebulA, and especially the white
ones like that in Andromeda, which have
not yet been resolved into stars, show a con-
tinuous spectrum; others are greenish and
give no lines.
A great deal has to be done by the chemist
before the astronomer can be on sure ground
in drawing conclusions from certain portions
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