Professor Huggins delivered his inaugural address to the British Association
in its Cardiff meeting on Wednesday, devoting it chiefly to his own special subjects,—the astro- nomical discoveries due to spectroscopic analysis and photo- graphy during the last quarter of a century. The address was rather too specialised to be easily followed by ordinary laymen, and seems to us more the kind of address which the head of the Astronomical Section should have de- livered to that section, than the address of the President to the Association as a whole. Professor Huggins gave a very interesting account of the speculations as to the age of the various stars of which we can make a, spectro- scopic analysis. He inclined to the view that the white stars like Sirius are stars in early life or their first maturity, while stars like our own sun and Capella are stars in "full maturity and commencing age ; " again, that the orange and red stars are stars in advancing age, cooling down towards dark- ness. Sirius emits from forty to sixty times as much light as our own sun, even to the eye,—which is insensible to the ultra- violet region in which Sirius is very rich. It is in a much earlier stage of existence, then, than our sun, though probably in a later stage than those white stars in which the hydrogen lines are bright. Professor Huggins tells us that even stars in the stage of our sun are not really yellow, but that the yellow tinge is given by our atmosphere, as the bluish- white rays pass through it.
Previous page
