THE NEW STAR IN THE ANDROMEDA NEBrLA. 355 



book being " a dim haze compressed into a ball of milky light at 

 the centre ; " but on turning the telescope on it on the night of 

 September 3rd a most wonderful change was at once apparent : 

 in place of the milky ball of light was a deep yellow star, of 

 about the 7th magnitude, which shone with a steady light, void 

 of the diffraction rings which surround stars on the dark back- 

 ground of the sky. It was at once apparent that a great 

 variation had occurred, and that we had here, either the conden- 

 sation of the bright nebulous matter into a brilliant sun, or that 

 one of the small stars previously alluded to had suddenly 

 increased in brilliancy ; like the famous star of Tycho Brahe 

 which appeared between Cepheus and Cassiopseia, in 1572. 



In considering the variation in the condition of this Nebula, 

 it becomes of great importance to ascertain what was the last 

 date at which it was observed in its original condition. 



We have seen that on August 9th I saw it apparently un- 

 changed, and in a communication from Dr. Copeland, the director 

 of Lord Crawford's observatory at Dun Echt, Aberdeen, I am 

 informed that " this is a welcome confirmation of a similar 

 observation of the same date /' at this epoch therefore there 

 can be no doubt that no starlike nucleus was visible, but the 

 change was near at hand ; Mr. Ward claims to have detected the 

 new star on Aug. 19th. M. Lajoye of Eheins saw it on Aug. 

 30th, Dr. Hartwig of Dorpat on Aug. 31st, Mr. Davis of Read- 

 ing on Sept 1st, and I observed it on Sej)t. 3rd, all being 

 independent discoveries. 



Its Magnitude and Colour. 



Like former stars which have blazed up, the brilliancy of 

 this star gradually diminished from the first, and its colour paled: 

 I judged it 7th magnitude on September 3rd, when it was with 

 attention faintly visible to the unarmed eye, and was a most con- 

 spicuous object even in a small telescope. On Sept. 27th it had 

 diminished considerably, and was not more than 8th magnitude, 

 whilst on Oct. 7th, it had still further declined to 8| magnitude. 



I have placed in the following table the estimates of the 

 magnitude of the "Nova" as rated by different observers, 

 together with the colours assigned to it, and although personal 

 equation causes difference in estimate, the fact of the decrease 

 in brightness, and alteration in colour is clearly shewn. 



