THE NB W STAR WHICH FADED INTO STAR-MIST. 109 



far more to blame than the author of the hypothesis. On 

 the other hand, it is very possible that an observer may, 

 involuntarily, arrest the progress of science, even without 

 originating an hypothesis, by pronouncing and publishing 

 sentences which have a tendency to diminish the general 

 interest in a question, and which do not place its high signi- 

 ficance in the proper light" (This is very neatly put) He 

 is " almost inclined to think that such an effect might follow 

 from the reading of M. Cornu's remark, and that nowhere 

 better than in the present case, where in short periods 

 colossal changes showed themselves occurring upon a 

 heavenly body, might the necessary data be obtained for 

 drawing useful conclusions, and tests be applied to those 

 hypotheses which have been ventured with regard to the 

 condition of heavenly bodies." It was, as we shall presently 

 see, in thus collecting data and applying tests, that Vogel 

 practically illustrated the justice of his views. 



The star which shone out in the Northern Crown in 

 May, 1866, would seem to have grown to its full brightness 

 very quickly. It is not necessary that I should here con- 

 sider the history of the star's discovery ; but I think all who 

 have examined that history agree in considering that whereas 

 on the evening of May 12, 1866, a new star was shining in 

 the Northern Crown with second-magnitude brightness, none 

 had been visible in the same spot with brightness above 

 that of a fifth-magnitude star twenty-four hours earlier. On 

 ascertaining, however, the place of the new star, astrono- 

 mers found that there had been recorded in Argelander's 

 charts and catalogue a star of between the ninth and tenth 

 magnitude in this spot The star declined very rapidly in 

 brightness. On May i3th it appeared of the third magni- 

 tude; on May i6th it had sunk to the fourth magnitude; 

 on the 1 7th to the fifth; on the iQth to the seventh; and 

 by the end of the month it shone only as a telescopic star 

 of the ninth magnitude. It is now certainly not above the 

 tenth magnitude. - 



Examined with the spectroscope, this star was found to 



