September 14, 191 1] 



NATURE 



347 



With regard to rainless thunderstorms, though no rain 

 falls, is that a proof that no rain has been formed? May 

 not rain have fallen from the clouds, but evaporated before 

 reaching the earth ? One sometimes sees after dry weather 

 clouds passing overhead from which rain seems to be fall- 

 ing, yet not a drop reaches the earth. If the thunder 

 clouds be high and the lower air very dry, such as we 

 have lately experienced, we can easily see that raindrops 

 will undergo evaporation while falling and may be dried 

 up before reaching the earth ; and as the horizontal direc- 

 tion of the movement of the thunder clouds is generally 

 different from that of the lower air, the falling rain may 

 not get a chance of saturating the lower air, even though 

 the storm may continue some time. 



For the benefit of those who may make a study of 

 thunderstorms, it may be of interest to record, as illustrat- 

 ing the influence of the geographical situation of a place 

 on the formation of thunderstorms, that the district round 

 Falkirk has a strange exemption from such storms. So 

 far as I can remember, there has only been one good 

 thunderstorm within my memory, and that goes back a 

 long way, and on that occasion the storm covered a great 

 part of the country. Once or twice in a year a few 

 distant peals may be heard ; and once this year we had 

 a storm which lasted half an hour, with about six peals 

 and some lightning, but that storm was an exception. 

 With the one exception above mentioned, there are no 

 great storms in that district such as are experienced in 

 most parts of the country. It should be mentioned that 

 Falkirk lies in the shallow valley connecting the Firths of 

 Forth and Clyde, through which it is proposed to cut the 

 low-level canal, and that there are no high hills near. 



John Aitkf.n. 



Loch Awe Hotel, Loch Awe, Argyllshire, 

 September 5. 



A Pseudo-Aurora. 



The explanation which Sir Lauder Brunton calls for in 

 No. 2183 of Nature seems to be very simple indeed. On 

 the evening of August 21, which he mentions, thunder- 

 storms of extreme violence came over the region of Lugano 

 and its environs. That region is due south-east of Beaten- 

 berg, as is also the Monch. The flashes seen were most 

 certainly those of lightning, and the auroral appearance 

 is very easily explained. Anybody may, in a mountainous 

 country, whenever there is a slight haziness in the atmo- 

 sphere, remark the shadows thrown on the mist by a light 

 — sun or moon — when still behind a mountain top, i.e. 

 rather low down in the sky. Such was the case with the 

 storm over Italian Switzerland, and the intense lightning 

 on August 21 was noticed as far away as the Canton de 

 Vaud. The flashes, lighting up the sky through the gaps 

 between the mountains, with the corresponding dark ravs 

 of tli" shadows, following in uninterrupted succession, may 

 well have given an impression of seeing auroral rays. 



J. S. Grey. 



Gryon-sur-Bex, Canton de Vaud, September 4. 



The Destruction of Kingfishers near London. 



I have just received a letter from a man who has been 

 very busy amongst the kingfishers that visit his grounds 

 within ten miles of the Bank of England. I enclose the 

 original letter, and now quote therefrom : — " I have caught 

 sixteen quite lately [apparently since the middle of 



August]. Six went to alive : the others I have 



skinned. Would you make me an offer for nine? " Since 

 receiving this letter I have been given three car. 

 understand that these birds were supplied alive to a dealer 

 by my correspondent ; this brings the total up to nineteen 

 birds, at least, removed from the bird-population of the 

 London district by one man. A disagreeable fact is that 

 all appear to have been killed not illegally. 



The weapon employed was. of course; the deadly " king- 

 fisher net " ; and my chief reason in writing this note is 

 to suggest that steps might well be taken to prohibit both 

 the use and the possession of this instrument. It is 

 practically useless for everything pxcept the capture of 

 kingfishers: and so simple is it to buy, or make, or us", 

 and so secret and so certain in its action, that by it*- 

 m^ans a man destitute of the elements of woodcraft could, 



NO. 2l85, VOL. 87I 



and frequently does, utterly clear a stream of its chief 

 feathered ornaments. 1 do not know of any fowling 

 engine more effective against its proper quarry than the 

 kingfisher net, nor can I think of one that needs less 

 actual supervision. This latter point explains why it is 

 so often in the hands of the unprivileged collector and the 

 poacher, and I have heard of it being used while its 

 owner and operator was actually under the constant eye 

 of a keeper — of course, one unaware of the intentions of 

 his suspect. 



I cannot think that I exaggerate if I say that the king- 

 fisher is the most defenceless of British birds, for no bird 

 is easier to kill. This is with the net ; without the aid 

 of a net an organised kingfisher hunt would be un- 

 remunerative, if not quite impossible, for many destructive 

 men do not dare to use a gun. Freed from the danger of 

 the net, the kingfisher would be in a peculiarly secure- 

 position, and would certainly increase until perhaps 

 common enough to be familiar by sight to all who have 

 the desire to see one alive. Its food consists of small 

 fishes and other aquatic animals, and the pisciculturist is 

 the only person who would suffer from the increase of 

 the bird. No good can come of attempting to ignore the 

 fact that in and about fish hatcheries the kingfisher is 

 an intolerable nuisance, and its destruction becomes at 

 times an economic necessity, for it is not always possible 

 to protect the fish by wire netting. But the prohibition 

 of the net need not prevent the killing of the birds, for 

 the keeper could easily use a gun. The kingfisher provides 

 a simple target, although, fortunately, its habits protect 

 it largely from the casual or wandering gunner. Without 

 loading this letter (which is no more than a hint or a 

 suggestion) with other details, I must end by saying that 

 I have often considered the matter in all its aspects, and 

 I believe that the total prohibition of the kingfisher net 

 would lead at once to an increase in numbers of this 

 ornamental bird, and that this prohibition would entail 

 no hardship on the pisciculturist, who is the only person 

 likely to be affected by the increase of the kingfisher. 

 Perhaps something could be done in this matter by those 

 who have the leisure to occupy themselves with the laud- 

 able work of active bird protection. 



Stepney Bosough Museums. Fredk. J. Stubbs. 



A Bright Meteor. 



Walking northwards on Saturday evening, September 2, 

 I was looking towards the constellation of Cassiopeia when 

 a bright meteor appeared at a point a few degrees west 

 of 1;" Perseus, and moved slowly westwards, gradually 

 increasing in brightness until its disappearance at a point 

 near a Canes venatici. 



Its maximum brilliancy was about four times that of 

 Jupiter, and its colour almost pure white. 



The time occupied in its transit was between six and 

 seven seconds, and a bright golden trail persisted for about 

 [wo ' ' .mil-; more. 



The time of the phenomenon was 2oh. 27m. (G.M.T.). 

 Wilfred C. Parkinson. 



The Observatory, Eskdalemuir, Langholm, 

 Dumfriesshire, September 4. 



Non-Euclidean Geometry. 



I owe sincere apologies for carelessness in the latter 

 portion of my letter in last week's issue of Nature. 



In hyperbolic space, the area of a circle of very 

 radius R appears as 



In Is 



'(cosh^-x), 



practically 



rKV 



which i* an exponential infinitude. 



On the other hand, the area of a regular N-gon inscribed 

 therein appears as something less than 



*-K s N, 

 which is 1 linear infinitude. 



Is not hvperbolic infinity paradoxical? 



W. B. Frankland. 



