CHAPTER VII.
POINTS IN SPECTROSCOPIC ASTRONOMY.
HE annual meeting of the British Association in 1891 had a peculiar interest for astronomers, inasmuch as the assembly at Cardiff was gathered together to hear an address on the subject of Modern Astronomy from the lips of one who is admittedly the founder of a great branch of astronomical physics.
There is no Englishman, there is no man of any other nation, who could speak with the same authority as Sir William Huggins on the achievements of the spectroscope in the exploration of the heavens. To realise fully what he has done we must contrast our present knowledge with the knowledge that was possessed thirty years ago. Up to the middle of the present century the progress of astronomy along the older lines had no doubt been marvellous. The discovery of Neptune had illustrated in a forcible manner the completeness of mathematical astronomy. The movements of the planets had become so thoroughly understood that, though here and there small discrepancies were recognised, yet it seemed that the difficulties remaining to be vanquished were
