But as regards the fate of worlds circling round suns which have suffered in this way, we can form but one opinion. Beyond all doubt, if such worlds existed and were inhabited when their central orb blazed forth with many hundred times its former lustre, all life must have perished from their surface. We may believe, as many do, that no conditions are too unlike those we are familiar with on earth to render life impossible; that the creatures subsisting in a world exposed to the most fiery heat or to the most intense cold are adapted as perfectly to the conditions under which they subsist as we are to the circumstances of terrestrial life. But even adopting this view, though it seems to accord ill with what we know of our own earth,--where life ceases towards the polar and over large tracts of the equatorial regions,--we could not believe that creatures thus adapted to the conditions prevailing around them could endure an entire change of those conditions. With the accessions of heat in the stars in Cygnus and the Crown, such change must inevitably have taken place. Therefore, as I think, we must regard the catastrophes affecting those remote suns as assuredly involving "The End of many Worlds." _Note._--What is stated in the latter portion of this chapter applies now only to the star in the Northern Crown; for the star in Cygnus has not faded into a small star, but into a small nebula! For the further history of this star, the reader is referred to my forthcoming treatise entitled, "Pleasant Ways in Science." FOOTNOTES: [7] Its place is indicated in my School Atlas, as well as (of course) in my Library Atlas, from the latter of which the small maps illustrating the present article have been pricked off. The new star is marked T in the Crown (Map VIII.), and must not be confounded with the star τ, as in Roscoe's Treatise on Spectral Analysis, and in some astronomical works. The star τ is a well known fifth magnitude star, which has shone with no perceptible increase or diminution of splendour since Bayer's time certainly, and probably for thousands of years before. [8] This chapter was first published in February, 1877, when the star was already invisible to the naked eye. [9] It will be remembered by those familiar with the history of solar observation, that when the spectrum of the solar prominence was first observed, the orange-yellow bright line was supposed to be the well-known double sodium line. It is so near to this pair of lines, that while they are called D 1 and D 2, it has been called D 3; and in a spectroscope of small dispersive power the three would be seen as one. [Illustration] VI. _THE AURORA BOREALIS._