294 



NATURE 



[July 27, 189; 



unequally so as to conduce to the same end is difficult to decide. 

 I may add that I have found the required muscles at the waist 

 consiilerably developed. F. W. Headley. 



Haileybury, Hertford, July 6. 



Remarkable Hailstones. 



On Saturday afternoon, July 9, a very violent storm burst 

 over Harrogate and its neighbourhood, accompanied by remark- 

 ably loud thunder and most brilliant and almost continuous 

 lightning. 



At first a little rain fell, but it was soon mixed with small 

 hailstones about the size of peas of the usual form. These were 

 quickly followed by hemispheres of the size and character 

 indicated in Fig. C. After a few minutes they rapidly grew to 

 the size of those shown in Figs. A and B, which are drawn very 

 carefully to actual scale. Most were flattened oval ciis;s, 

 as Shawn in the two drawings, which exhibit top and side view 

 of one hailstone. I went out myself and measured a gocd 



number while they were falling by putting them on a sheet of 

 paper and marking their maximum and minimum diameters. 

 These large stones usually had an opaque spherulitic-Iike nucleus, 

 followed by two, three, and even a trace of a fourth clear ice 

 shell intervening with opaque ice. Then followed a broad 

 band of clear ice with a few radiating air cavities, finally 

 enclosed in a mass of white granular feathery ice. The number 

 of alternating laminoe seemed to be irregular, and must have 

 varied with that of the different vapour strata traversed by each 

 nucleus. The origin of the type (Fig. A from Fig. C) is very 

 obvious. The quantity that fell was enormous, so that a lawn 

 badly kept was entirely white, with the exception of the longer 

 blades of grass that projected. The damage done in the near 

 neighbourhood must amount to some thousands of pounds, and 

 very few are the houses in this town that escaped without win- 

 dows being broken. I did not time the duration of the fall, 

 but I think it was about an hour. 



S, Princes Square, Harrogate. H. J. Johnston-Lavis. 

 July 12. 



NO. 1239, VOL. 48] 



A Substitute for Ampere's Swrimmer. 



I HAVE long been dissatisfied with the rules commonly given 

 in order to enable the relation between the direction of a current 

 and that assumed by a magnet in its neighbourhood to be readily 

 brought to mind. It is a small matter, but it causes a great 

 deal of worry to many a student. The vagaries of Ampere's 

 swimmer are "past the wit of man." Prof. Jameson's rule is 

 not bad, but is not really easy to remember ; the corkscrew is 

 good, provided that you have a little time to think about it ; 

 but I have felt all along that it ought to be possible to devise 

 something simpler than any of these. May I suggest that the 

 following may perhaps be found useful ? 



If a pen be held in the right hand in the usual way, the pen- 

 holder may be taken to represent the wire, and the direction of 

 the flow of ink (that is, towards the point of the pen) the direc- 

 tion of the current ; if, then, the thumb be stretched a little 

 across the penholder it will represent the magnet, and the 

 thumb-nail its marked or north-seeking pole. The hand may, 

 of course, be twisted round into any position to represent any 

 actual case. The same relation may be still more simply borne 

 in mind by dispensing with the penholder, and merely laying 

 the thumb across the forefinger of the right hand ; either of these 

 will then represent the current (flowing towards the finger, or 

 the thumb-nail, as the case may be), the other the magnet. 

 1 Whether this is novel I do not know ; it is so as far at I am 

 ! concerned ; but I think it is useful. Alfred Daxieli. 



Advocates' Library, Edinburgh, July 13. 



The Jelly-fish of Lake Urumiah. 



In Mr. Curzon's recently-published work "Persia and the 

 Persian Question " (vol. i. p. 533), he writes as follows .— 

 "When the wind blows on Lake Urumiah, sheets of saline 

 foam are sqen scudding along the surface, and the salt is left 

 upon the shore in a solid efflorescence, sometimes several inches 

 thick. No fish or molluscs live in the waters, whose sole living 

 contents are a species ai small jelly-fish, which sustain the swans 

 and wild fowl that are occasionally seen." 



When Captain F. R. Maunsell read his interesting paper on 

 Kurdistan to the Royal Geographical Society in June las", I 

 asked him whether he could give me any further information 

 respecting this so-called "jelly fish," to which he was kind 

 enough to reply as follows : — " In reply to your inquiries re- 

 garding the existenceof a jelly-fish in Lake Urmia, I have been 

 going through my notes, and find that I visited the lake on 

 July 20 at its west shore, not far from the town of Urmia. I 

 bathed in the lake and found the jelly-fish in great numbers 

 along the shores where the water was shallow. It was only 

 about half an inch in diameter, of a greenish-white, almost 

 colourless, with a small black centre. There are said to be no 

 fish or other living creatures in the water, and I did not see any. As 

 you probably know, the lake is extremely salt, more so than the 

 Dead Sea. The specific gravity is given as I'I55, with 21-4 

 per cent, of salt. The lake is 4,100 feet above the sea level, 

 and has no outlet. There is a British Consul in Tabriz, which 

 is not far from the east shore of the lake, who might obtain a 

 specimen, and would be able to ensure its getting home safely 

 better than any one else. The lake is very shallow compared 

 with its great size, nowhere ^eing more than from thirty to forty 

 feet in depth." 



The only instance of a "jelly-fish " or Medusa as yet 

 known to inhabit an inland sea is that of the Limnocnida tan- 

 ganjiccc, recently described by Mr. R. T. Giinther (Ann. and 

 Mag. N. H. ser. 6, xi. p. 274(1893)). It would be therefore 

 of great interest to obtain specimens of the "jelly-fish" of Lake 

 Urumiah and ascertain what it really is. 



3, Hanover-square, W., July 17. P. L. Sclater. 



Racial Dwarfs in the Pyrenees. 



Being on the Riviera when I received Natitre of January 

 26 with Mr. Haliburton's letter on the above subject, I pro- 

 posed to act on his suggestion, and. on my way back to England, 

 to explore the region indicated. To ensure, however, that the 

 proposed exploration should not be a wild-goose chase, I first 

 entered into communication with all the British consuls and 

 French savants likely to have special knowledge of the subject, 

 and more particularly with M. Cartailhac, director of /'.-/«//»'''- 

 fologie, and who resides at Toulouse, "within little more than a 



