562 SCIENCE PROGRESS 



as No. 1 8 in the list of Novae which had been discovered in 

 the history of astronomy. 



Readers of the daily press will probably have seen recently 

 an announcement of a similar discovery by the Rev. T. E. Espin, 

 of Darlington, which is No. 22 in this list ; for during the 

 past autumn no less than three special objects were discovered 

 at the Harvard Observatory from the examination of photo- 

 graphic plates. The total number is, however, still not large, 

 though from the facts that up to the year 1884 only eight had 

 been recorded and that the other sixteen have all been found 

 in the last quarter of a century, we may infer that the rarity is 

 partly due to our own lack of vigilance, and that the few dis- 

 coveries recorded would probably have been supplemented by 

 many others had a more systematic watch been kept. 



We are at present not very well informed as to the nature 

 of the celestial event which is represented by the appearance of 

 a new star. A few things about it we know. In the first place 

 the event is a sudden one, the light of the star increasing 

 enormously within a day or two by something like twelve magni- 

 tudes — that is to say, in a ratio of about i to 80,000 — then the 

 light slowly diminishes — slowly but not quite steadily ; there 

 are fluctuations in the course of the diminution and these 

 fluctuations were specially noticeable in the case of the new 

 star of 1901— in Perseus. Sir Robert Ball gave us, at the Royal 

 Astronomical Society, an amusing account of his experiences 

 at the time when the fluctuations were such as would cause 

 the star first to disappear to the naked eye and then to reappear 

 again. He had taken a party of visitors into the open to show 

 them the new star, only to find that it had disappeared ; on 

 the next night he took out another party to show them the 

 disappearance and, as though to spite him, it had reappeared 

 again. But these were only temporary vagaries, as the star 

 was soon permanently lost to our sight and then even to 

 telescopes of moderate power. It still remains, however, as a 

 very faint object visible in large telescopes. 



Another incident in the history of this particular new star 

 may be noticed, for it seems to tell us something about the origin 

 of such objects. When the light had become very faint, so that 

 photographs of the region were necessarily taken with long 

 exposures, there was found to be a faint nebulous light sur- 

 rounding the star and successive photographs showed that this 



