PROGRESS OF MODERN ASTRONOMY 



vealing the telltale lines sprinkled across a prismatic 

 spectrum, discloses the chemical nature and physical 

 condition of any substance whose light is submitted to 

 it, telling its story equally well, provided the light be 

 strong enough, whether the luminous substance be near 

 or far in the same room or at the confines of space. 

 Clearly such an instrument must prove a veritable 

 magic wand in the hands of the astronomer. 



Very soon eager astronomers all over the world were 

 putting the spectroscope to the test. Kirchhoff him- 

 self led the way, and Donati and Father Secchi in Italy, 

 Huggins and Miller in England, and Rutherfurd in 

 America, were the chief of his immediate followers. 

 The results exceeded the dreams of the most visionary. 

 At the very outset, in 1860, it was shown that such 

 common terrestrial substances as sodium, iron, calci- 

 um, magnesium, nickel, barium, copper, and zinc exist 

 in the form of glowing vapors in the sun, and very soon 

 the stars gave up a corresponding secret. Since then 

 the work of solar and sidereal analysis has gone on 

 steadily in the hands of a multitude of workers (promi- 

 nent among whom, in this country, are Professor 

 Young of Princeton, Professor Langley of Washing- 

 ton, and Professor Pickering of Harvard), and more 

 than half the known terrestrial elements have been 

 definitely located in the sun, while fresh discoveries 

 are in prospect. 



It is true the sun also contains some seeming ele- 

 ments that are unknown on the earth, but this is no 

 matter for surprise. The modern chemist makes no 

 claim for his elements except that they have thus far 

 resisted all human efforts to dissociate them ; it would 



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