362 



NATURE 



\Ang7tst 19, 1880 



intensily were cliaracteristic of aurora, which is not very common 

 at this season of the year, I thin!:. F. T. MOTT 



Birstal Hill, Leicester, August 13 



We had a fine aurora here last night (nth). There was a 

 bright banli of uniform glow till II p.m., when it suddenly 

 broke into streamers, some of which reached 40° or 45° in height, 

 the glow extending along 100° or 120° of the horizon. There 

 was no colour, and by midnight it had all faded out. 



Whitby, August 12 ,,__ B. W. S. 



Height of the Aurora 

 I SHALL be glad if you will allow me the use of your columns 

 to point out that there is really less uncertainty about this 

 element than is usually supposed, and that there are two methods 

 of measuring auroral heights which give accordant results. The 

 first is that based upon the measurements of the altitude 

 and amplitude of auroral arches, and which gives the results 

 mentioned by Mr. Rand Capron. That these results should 

 have so wide a range is probably owing to the fact that they 

 proceed upon an assumption which may or may not be correct, 

 viz., that the arch is part of a circle having the magnetic pole for 

 its centre. Still the mean result from this method would seem 

 to be reliable, especially if care were taken to exclude doubtful 

 measurements from the list. Possibly we may assume that this 

 method gives a height [not far from 100 miles for the ordinary 

 arch. I speak particularly of the white auroral arch with or 

 without uncoloured streamers that forms, I suppose, 95 per cent, 

 of the auroral phenomena visible in this country. These arches 

 are formed for the most part over a portion of the earth con- 

 siderably to the (magnetic) north of these islands, but occasion- 

 ally they would seem to be formed over our heads. Mr. Capron 

 in his work on "Aurora: and their Spectra" mentions one such 

 instance, though he appends no explanation of the phenomenon, 

 but in the course of ten years' obsen'ations I have myself seen 

 three such arches. Indeed they are perfectly well known to 

 observers in Scotland and the north of England, though I have 

 never Sten them in the south. As early as the year 1S43 "*^ 

 height of these zenithal arches had been trigouometrically com- 

 puted from observations made in different localities in Britain, 

 with the result of proving them to be at an uniform height of 

 70 to 74 miles above the earth.^ There is much less liability to 

 error in these results than in the determination of the height of 

 a meteor, and a single pair of satisfactory observations will yield 

 a value within one or two miles of the actual elevation. 



That auroral arches are ever formed much below this limit I 

 beg leave to doubt. 1 am aware of the accounts which would 

 place them between the eye and natural objects, but such asser- 

 tion ^ are far from having the weight of accurate measurements, 

 and I have yet to find a case of a supposed low aurora, the 

 evid :nce of which is above criticism. ■ 



I do not wish to assert that the streamers at ri^ht angles to 

 these arches may not be frequently visible at a less height, just as 

 they undoubtedly reach to a much greater elevation in the region 

 where the auroral crown is formed. But to fix either the 

 superior or inferior limit is precisely one of those questions 

 which we can have no hope of solving by direct measurement, 

 since the length of the streamer varies with the force of electric 

 discharge. This is shown by the fact that in an active aurora 

 some streamers extend only a short distance from the arch, 

 while others will climb up to the vanishing point, or crown. 



To carry these remarks so as to include the question of 

 coloured aurora: would oblige me to trespass more upon your 

 space than I am willing to do on this occasion. 



Orwell Park Observatory, Ipswich John I. Plummer 



Fire-Bail 



On the evening of the 12th a very brilliant fire-ball fell at 

 Sh. 30m. G.M.T. It was first observed at an elevation of about 

 25° above the E.S.E. horizon, and its path was inclined at an 

 angle of about 35° to the horizon. It was lost in the mist near 

 the south horizon. There was no explosion or noise of any 

 kind. The daylight was still fairly strong, and yet the light of 

 the meteor was very dazzling. S. J. Perry 



Stony hurst Observatory, August 15 



' I give these figures from memorj'. as I h.-ive no library at hand to which 

 to refer, but I have no doubt that they are strictly correct. Mr. Capron 

 may perlu-ips find some information on the point in the published works of 

 the late Prof. Phillips, who was one of the observers engaged in these 

 investigations about the date I have named, or Ihey may be verified upon 

 the first appearance of a lenithal arch. 



Atmospheric Phenomenon 



A CURIOUS phenomenon was observed here after sunset the 

 night before last, and again in a less degree last night. 



Looking across from this point to the position of the sun at 

 and after setting, the line of sight crosses about three miles of 

 sea, then about the same distance or rather less of projecting 

 high ground, and beyond that many miles of sea again. On Tues- 

 day (loth) the sun set in a hot haze, and half an hour after there 

 appeared on the edge of the projecting land what looked like 

 tongues of flame fifteen to thirty minutes in height, lasting from 

 two to four seconds each, and then disappearing in different 

 places, sometimes half a dozen at a time. At the same time 

 there was more or less of a flickering light along the whole line 

 of projecting land. 



My first impression was that it was an optical illusion, and the 

 second that a moor was on fire behind the ridge, and that these 

 were points of flame. The first was negatived by the fact that 

 four others beside myself (two of them with very keen sight) 

 saw the lights independently in the same places ; and the second 

 by the gradual fading of the light as the evening became darker, 

 the "tongues" retaining pretty much their relative brightness to 

 the general glow until both faded out. 



The day had been extremely hot, and the evening was sultry, 

 with motionless air. I imagine the appearance was due to 

 irregular refraction, arising from heated currents of air from the 

 cooling land, and that the circumstance of the slice of land with 

 its currents occurring between the two stretches of homogeneous 

 air over the sea allowed the effect to be seen without being 

 masked, as it would have been had there been intervening land. 

 But I never saw it before, and don't remember to have seen it 

 described. B. W. S. 



Whitby, August 12 



Intellect in Brutes 

 Instinct apart, cases of intelligence in animals are very 

 numerous, of the affections still more numerous. Comte was of 

 opinion that the affections were even more highly developed in 

 animals than in men. The dog will lay down life for the man 

 he loves, the horse will do so likewise. We have all heard of 

 Greyfriars Bobby, if that be the creature's name. But instances 

 crowd on the memory. A few years back, during a heavy gale, 

 a sweep of the spanker-boom drove the master of a Leith and 

 London smack into the sea. Instantly the ship's dog bounded 

 in after, and, sustaining the drowning man, both passed grandly 

 into the eternities together. I have known cats who let them- 

 selves into the dwelling-hou-e at pleasure, and at least three dogs 

 w Iio were wont to deposit the pennies given them on the counter 

 of some baker or pastry-cook in return for values received. I 

 used to meet on the highway a dog who rode behind his master's 

 groom. The hardest trot never seemed to discompose his seat. 

 Even birds — not merely trained birds — sometimes display singu- 

 lar attainments. I knew a lady vho had a singing duck, but 

 being one day at a loss for a couple, she sacrificed the songstress 

 to make up a pair. One wishes that she had displayed a little 

 more humanity ; as also a clergyman, not a hundred miles from 

 w'here I sit, v ho ordered a goose that had evinced the w'armest 

 attachment to be slain by reason of the poor bird having followed 

 him on the occasion of paying a visit into a friend's drawing- 

 room. 



When a boy I used to spend many a holiday at a farmer's 

 house in the County Armagh. I there experienced gi'eat kind- 

 ness, enjoying myself as much as was well possible in the open 

 air, the garden, and the stubble fields. Besides human beings,:! 

 had numerous playmates too in the kine, swine, dogs, fowl, 

 horned cattle, and horses about the place, and indeed was never 

 tired in observing their modes of living and acting. The great 

 housedog used often to play with a large hog. They alternately 

 chased and faced one another till the hog's chaps would froth 

 again actually with the excitement of the sport. At first I 

 supposed that the pig did not like it, but in this I was mistaken. 

 One day a strange dog, an immense brute, made his appearance, 

 and attacked the house-dog, who was evidently getting the 

 W3rst of it, when who should come to the rescue but the hog, 

 who instantly jumped on the strange dog's back, ass.ailing him at 

 the same time with hoof and tooth. Placed thus between two 

 fires, the stranger beat a speedy retreat, leaving the friends 

 complete masters of the situation. 



I think I was abaut ten years old when my parents went to 

 reside at a place called Fairlawn, situated on a gentle eminence 

 a few miles from tlie mutually contiguous towns of Moy and 



