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tensified. He also found that, if he used a
limelight instead of the sunlight and passed
it through the flame with salt, the spectrum
showed the D line black; or the vapour of
sodium absorbs the same light that it ra-
diates. This proved to him the existence
of sodium in the sun’s atmosphere.[4] Iron,
calcium, and other elements were soon de-
tected in the same way.
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