262 . Mr. Christie on the Aurora Borealis 



one of its legs, so that it was from its incapability to rid itself 

 of these insects that their extraordinary increase was to be 

 attributed. A circumstance of a similar kind also came under 

 my notice connected with a swallow's nest. After the young 

 birds had been hatched, and had attained a certain size, a 

 change was made in the arrangement of the window, which 

 frightened the parents : from that time they continued to feed 

 their offspring, but never entered the nest ; and I soon observed 

 that the young ones were sick, and one by one they perished. 

 I then took the nest down, and found it crowded with acari, 

 which were of a very great size compared with that of the bird 

 itself. I could only attribute this fatal increase of vermin to 

 the old birds having been prevented cleaning out the abode of 

 their family. 



Poultry which run about in stony or paved yards, wear away 

 the points of their claws by friction and digging, which renders 

 them unfit to penetrate their coating of feathers ; they are, 

 therefore, more covered with vermin, and in consequence more 

 sickly than fowls from the country. 



ON THE AURORA BOREALIS OF THE ?TH OF JANUARY, 1831. 

 BY S. H. CHRISTIE, ESQ., M.A., F.R.S., &c. 



[To the Editor of Q. J.of Science, &c.] 



Woolwich Common, 1th January ', 1831. 



"YTDU will not, I think, be sorry to have some account of the 

 appearance of the very beautiful aurora of this evening, 

 in this neighbourhood, where, perhaps, I had a better oppor- 

 tunity of viewing it than you might have in town. I was not, 

 however, under very favourable circumstances for making 

 remarks upon it, as I was, for a considerable part of the time 

 during which it appeared, travelling, being outside of our coach. 

 I first observed it at 5h. 30m., being then on Blackheath, 

 about half a mile S.W. from the observatory. At this time I 

 observed a strong white light, resembling the tail of a comet, 

 but denser, like a light cloud illuminated by the moon, pro- 

 ceeding from near Betelguex in the east towards Aldebaran. 



