The reader is no doubt aware that when the light of a star is analysed into its component colours by the instrument called the spectroscope, it is found that all the colours of the rainbow are present, as in the case of solar light, but (also in the sun's case) not all the tints of these colours. Certain dark lines athwart the rainbow-tinted streak, called the _spectrum_ of the star, indicate the presence of absorbing vapours in the star's atmosphere. This general statement is true of every fixed star, though the dark lines of some stars differ in number and position from the dark lines of others, showing that other absorbing vapours are present. In the case of the new star in the Crown, the usual stellar spectrum was shewn,--a rainbow-tinted streak crossed by a number of dark lines. But besides these, there were seen four very bright lines,--lines so bright that the rainbow-tinted streak appeared as a dark background. The meaning of this is well understood by spectroscopists. It signifies that besides the vapours which, being cooler than the star, absorbed a portion of its light, and produced the dark lines, some vapours were present in the star's atmosphere which were a great deal hotter than the star, and so produced bright lines. Now two of the lines corresponded in position with two of the well known lines of the gas hydrogen, showing that this was one of the gases which had been raised to an unusual degree of heat. It was inferred that there had been some tremendous disturbance in that remote star, by which the hydrogen and some other vapours present in its atmosphere had been intensely heated. But astronomers were unable to decide whether the disturbance was of the nature of a conflagration, the hydrogen actually burning, or whether the heat was occasioned in some other way, as by the downfall of some immense mass upon that remote sun. For burning hydrogen and glowing hydrogen, though either could give the observed bright lines, are very different things. In the former case a chemical change is taking place, as in the case of burning wood or coal; the latter case resembles that of redhot iron, which is not burning itself (not changing into a different form as everything does which burns), though it will burn other things,--in the ordinary, and incorrect, use of the expression. The general belief was that there had been a downfall of matter on the star in the Crown, by which the whole globe of that sun had been excited to an intense degree of heat, especially at the surface, near which lies the hydrogen atmosphere of the star.