THE NEW STAR WHICH FADED INTO STAR-MIST. 107 



lively. A new era seems indeed to be beginning for those 

 departments of astronomy which deal with stars and star- 

 cloudlets on the one hand, and with the evolution of solar 

 systems and stellar systems on the other. 



Let us briefly consider the history of the star of 1866 in 

 the first place, and then turn our thoughts to the more 

 surprising and probably more instructive history of the star 

 which shone out in November, 1876. 



In the first place, however, I would desire to make a few 

 remarks on the objections which have been expressed by an 

 observer to whom astronomy is indebted for very useful 

 work, against the endeavour to interpret the facts ascertained 

 respecting these so-called new stars. M. Cornu, who made 

 some among the earliest spectroscopic observations of the 

 star in Cygnus, after describing his results, proceeded as 

 follows : " Grand and seductive though the task may be 

 of endeavouring to draw from observed facts inductions 

 respecting the physical state of this new star, respecting its 

 temperature, and the chemical reactions of which it may be 

 the scene, I shall abstain from all commentary and all hypo- 

 thesis on this subject. I think that we do not yet possess 

 the data necessary for arriving at useful conclusions, or at 

 least at conclusions capable of being tested : however 

 attractive hypotheses may be, we must not forget that 

 they are outside the bounds of science, and that, far from 

 serving science, they seriously endanger its progress." This, 

 as I ventured to point out at the time, is utterly inconsis- 

 tent with all experience. M. Cornu's objection to theorizing 

 when he did not see his way to theorizing justly, is sound 

 enough ; but his general objection to theorizing is, with all 

 deference be it said, sheerly absurd. It will be noticed that 

 I say theorizing, not hypothesis-framing; for though he 

 speaks of hypotheses, he in reality is describing theories. 

 The word hypothesis is too frequently used in this incorrect 

 sense perhaps so frequently that we may almost prefer 

 sanctioning the use to substituting the correct word. But 

 the fact really is, that many, even among scientific writers, 



