60 KNUT LUNDMARK, GLOBULAR CLUSTERS AND SPIRAL NEBULA. 



astonishing in the fact the Nova Andromedae 1885 reached a magnitude, which 

 differs only by 2 classes of magnitude from the magnitude of the nebula itself. 



On the appearance of the Nova Andromedöe 1885 Charlier referred to a rare 

 old publication 28 which shows that a nova had probably appeared in the Andromeda 

 nebula in 1664. We will give a short account of the contents of this paper. 



Bullialdus points out how, at the appearance of the comet of 1664, the 

 astronomers discovered a new phenomenon, viz. a nebula which appeared in the belt 

 of Andromeda. According to the author it cannot be counted among the faint and 

 insignificant phenomena, and it has been observed earlier by Simon Marius in 1614, 

 whose observations regarding this object are quoted. With Marius the author is 

 astonished that Tycho Brahe has not mentioned the Andromeda nebula, and as 

 Hipparchos and Hevelius and many others do not seem to have observed it, the 

 author concludes that it appears and disappears alternately. The author has found 

 a manuscript to a står catalogue with drawings of the constellations, and in the 

 representation of Andromeda the unknown drawer, who, according to Bullialdus, 

 cannot have been living much earlier or much låter than 1500, has represented the 

 nebula with döts in the same manner as he has in the same work drawn the nebula 

 (står duster) in the Cancer (Praesepe). Bullialdus adds: 



»From what has been said, I conclude that this nebula has been observed by 

 some astronomers 150 years ago. As, however, it has not been noticed either by 

 Hipparchos or by any other ancient scientists, and neither in the last century has 

 been drawn by Tycho Brahe, the generalissimo of the astronomers, nor in our time 

 by Bayer, and as even at this moment, in November 1666, it looks quite obscure and 

 insignificant ajter two years ago having shone exceedingly bright, it follows with neces- 

 sity, that it appears and disappears by intervals.» 



Any great amount of importance ought perhaps not to be attached to the, 

 nevertheless, curious circumstance that the nebula has not been observed by Brahe, 

 Hevelius, and Hipparchos, but, on the other hand, the author's express statement 

 that the magnitude of the nebula in 1664 was exceptionally high, seems to indicate 

 that just then some nova of extraordinary magnitude had flashed up within the 

 nebula. If we suppose the total magnitude of the nebula to be 5"\o, and if we 

 suppose that a nova of the magnitude 6,o has appeared in the nebula, we conclude 

 that the nebula, during the appearance of the nova, should have had a total magni- 

 tude of nearly 4™,6. This difference in the magnitude of the nebula should, of course, 

 easily be noticed by an observer accustomed to observe the sky. Besides, nothing 

 prevents us from assuming a still greater upper limit for the maximum magnitude 

 of a nova than was the case with that of Tycho Brahe. 



0. The Magellanic Glouds. 



If we finally start from our already suggested hypothesis that the Magellanic 

 clouds are spiral nebulse (Pl. 1) and the nearest hitherto known, we thereby obtain 



