June i8, 1891] 



NATURE 



151 



evening, which showed that the upper current had changed to 

 south-east. No observations could be made during the two wet 

 days which followed ; but early in the morning of the 27th, when 

 the centre was about loo miles to the north, true cirri were 

 observed moving slowly from north-east. These soon disap- 

 peared ; but at 6 p.m. of the same day an important change 

 took place, the bands of icecloud moving from south-south-west, 

 from which point, or from a little west of it, the belts have con- 

 tinued to travel up to the time of my writing this, the lines being 

 nearly parallel to the isobars, and to the general direction of the 

 surface winds, and precisely resembling in character the stripes 

 seen in most cases travelling from north -north-west when a 

 depression, whose centre has passed a little to the north of the 

 observer, has moved away to north-east.^ 



(3) In an elaborate paper in the Quart. Journ. of the R. 

 Met. Soc. for October 1877, the writer pointed out that in the 

 extreme left-hand segment of an approximately circular cyclone, 

 moving in any direction in the northern temperate latitudes, the 

 movements of the upper currents are by no means analogous to 

 those in the right-hand segment.^ In the case of cyclones tra- 

 velling eastwards, the reason of this difference is, I think, now 

 well understood. Owing to the great relative density of the 

 lower atmosphere, attended with low barometric pressure, near 

 the poles, the gradients for westerly currents are far more con- 

 stant in the upper than in the lower strata of the atmosphere in 

 the regions traversed by extra-tropical cyclones. Over a large 

 number of these cyclones, therefore, many of the isobars in the 

 upper regions of the atmosphere do not form closed curves, but 

 curves somewhat resembling those which, at the earth's surface, 

 accompanying what are popularly termed V-shaped depressions. 

 It is a question of the utmost interest whether, during the periods 

 in which depressions travel to the west, the distribution of 

 gradients in the upper atmosphere is really for the time reversed, 

 and, if so, what can be the causes of so remarkable a change. 

 There is a further question correlated with the above, which 

 deserves more attention than has been given to it. The writer 

 long ago pointed out (Journ. Scot. Met. Soc, vjl. iv. pp. 333- 

 335) that in cases of depressions travelling westward across our 

 islands, temperatures at the earth's surface are in general higher 

 over Scandinavia than over France ; and a considerable number 

 of instances have occurred since 1875 which have confirmed this 

 conclusion. But in most of these cases an anticyclone ha> 

 lain to the north-east of us, so that the "gradient force" of the 

 lower strata may have tended to send the depression westwards, 

 in addition to the ascensional force, assiciateJ with condensa- 

 tion in the western segment, due to the indraught of relatively 

 warm air from north and north-east. In the instance described 

 in this paper pressure was not particularly high over Scandi- 

 navia, during the westward progress of the system, but tempera- 

 ture seems to have been higher, over Sweden at least, than in 

 France. W, Clement Ley. 



May 30. 



The Crowing of the Jungle Cock, 

 I.^f Nature (vol. xliii. p. 295) Mr. Henry O. Forbes has a 

 letter commenting on a statement of Mr, Bartleit to the effect 

 that the wild jungle cock does not crow, and testifying that he 

 once heard one. In reply, in the next number of Nature, it 

 was suggested that the cock heard by Mr. Forbes was a hybrid. 

 I think that no one who has travelled in the jungles of Burma, 

 during the dry season, can have any doubt that the jungle cock 

 crows ; for he cannot fail to have heard them many times. 



It so happens that, just after reading Mr, Forbes's letter, I had 

 occasion to travel among the hills which form the watershed 

 between the Irrawaddy and the Sittong rivers. In one region 

 here a large kind of bamboo was seeding, so that the jungle 

 fowl were very numerous, and I heard them crowing in great 

 numbers. I remember one place in particular : the Karens had 

 prepared us a hut in which to sleep just outside of their village, 

 which consisted, like nearly all the villages in these hills, of a 

 single house, each family having its separate room in the common 



' These stripes ot clrro-filutn are so abundant in the rear of most de- 

 pressions, towards the termination of the inversion disturbances accompany- 

 U15; saualls or thunder-showers, in Eiirops and the Northern States that it is 

 singularly unfortunate that the statenisnt of an English meteorologist, to the 

 eflfect that they di not exist, sh:)uld have found its way into the first edition 

 of Ferrel's " Popular Treatise on the Winds." 



» See also Ferrel, " Pjp. Treat.," § i3o; "Modern Meteorobgy," p. lit 

 (diagram). 



NO. II 29, VOL. 44] 



building. " At cock crowing " in the morning we had, close to 

 us, the crowing of the village cocks, and on every side, far and 

 near, the answering crows of multitudes of wild birds, I do not 

 remember ever to have been treated to such a chanticleer concert 

 before. 



The idea that these wild cocks were all hybrids is inadmissible, 

 because (i) they were so very numerous, and (2) the country is 

 very sparsely peopled, the villages all being small and far apart, 

 and the greater part of the country still covered with primaeval 

 forest. 



The crow of the jungle cock is shrill, like that of the smallest 

 breeds of domestic fowl, and is, perhaps, a little less prolonged 

 than that of the average domestic cock ; but it can hardly be 

 distinguished from the crow of a small breed of fowl kept by the 

 Karens, some individuals of which so closely resemble the wild 

 fowl that they are used as decoys. 



I have several times heard wild fowl cackle, and in this 

 journey, while in the midst of a heavy forest, miles from any 

 human habitation, we came upon a flock of wild fowl cackling, 

 and could tell by the tones that both cocks and hens were cack- 

 ling. One of the followers beiiig sent with a gun to try and get 

 a shot, some of the birds saw him and flew, whereupon one of 

 the cocks gave the peculiar call which the domestic cock gives 

 when a bird flies over him. 



I might add that, among the numerous birds shot in this 

 region, there was one hen which had a pair of spurs about 

 half an inch long. B, P. Cross, 



Rangoon, May 20, 



Cordylophora lacustris, 



I r is generally believed that this tube-dwelling Hydrozoa was 

 originally a salt-water animal, and although now found a con- 

 siderable distance from tidal water, it still dwells in rivers and 

 canals more or less connected with tidal rivers. I have for 

 many years found it in the Chester and Ellesmere Port Canal, 

 growing principally on the shells of the fresh-water mussel, from 

 two to three miles from the tidal river (the Dee). It seems to 

 be a shade-loving animal, as I have always found it under the 

 bridges, and from 4 to 6 feet beneath the surface of the water. 



The tubes only remain during the winter and early spring, 

 and the animal is fully developed in August and September. 

 It is generally accompanied by Fredericella sultana. 



Thomas Shepheard, 



Kingsley Lodge, Chester, June 12. 



Philosophical Instrument Makers. 

 I FIND in your paper of June u (p. 135) that Messrs, Newton 

 and Co. have been appointed philosophical instrument makers 

 to the Royal Institution of Great Britain, Allow me to state 

 that they are not the only ones, and that I also was appointed 

 on June i by the managers of the Royal Institution of Great 

 Britain to be their philosophical instruoient maker. I thought 

 that in the interest of the public you should know this fact. 



A. HiLGER. 



204 Stanhope Street, Hampstead Road, June 12. 



The Earthquake of June 7. 



The earthquake of June 7, whose centre seems to have been 

 in the province of Verona, was also perceptible at Basle, The 

 seismometer of the Bernoullianum Observatory registered a 

 horizontal shock at ih. 47m. 29s. a. Basle mean time, which 

 corresponds to ih. 17m. los. Greenwich mean time. 



At Thai, a village east of St, Gall, the shock was strong 

 enough to t)e felt by several persons, 



Basle, June 13, A, Riggenbach-Burckhardt. 



NOTE ON EGYPTIAN IRRIGATION. 



IN entering upon any account of Egyptian irrigation it 

 is necessary, at first, to point out that it consists of 

 two very broad subdivisions : (i) the irrigation effected 

 by the Nile flood when there is rich muddy water in 

 abundance for a land thrice as big as Eg>pt, and when 

 everyone considers it his absolute right to have his fields 



