March 9, 191 1] 



NATURE 



45 



Reflections in Water. 



In the coloured photographs from Egypt, printed in The 

 Illustrated London News on February 25, one picture has 

 white clouds and blue sky with their reflection in still 

 water. The image has the appearance of being stronger 

 than the original. The fact is that the blue sky has much 

 more polarised light than the clouds : the cross-polarisation 

 by reflection at the water darkens the sky and scarcely 

 alters the clouds. At the various incidences, by which the 

 different points of the sky reach us, the conditions are 

 altered. Thus the reflected scene is one of greater variety 

 and stronger contrasts. The effect is not due to anything 

 in the photographic process ; I was surprised to see such 

 a correct presentation of what I have sometimes observed. 



No one could surpass the late Lord Tennyson in his 

 love for noting various moods of nature, but perhaps the 

 habit is more frequent with great masters of language in 

 France than with us. Pierre Loti abounds with such 

 passages as " Avec cette sonority particuli^re que les 

 cloches prennent pendant les nuits tranquilles des prin- 

 temps." Rostand devotes the opening verses of 

 " Chantecler " to the varied powers of sunlight : the sink- 

 ing sun, for instance, which chooses 



L'humble vitre d'une fenetre 

 Pour lancer son dernier adi^u. 



There are two marked forms in which we often see this. 

 Sometimes it is difficult to believe that there is not a 

 fierce red fire raging in a distant house. At other times, 

 with a higher and a whiter sun, a house on the hill may 

 reflect the sun to us, surrounded with brilliant coloured 

 halos. I suppose that dust upon the window diffracts the 

 light, as do the dust plates of Fraunhofer. 



The College, Winchester. W. B. Croft. 



A Self-regulating Siphon. 



Im a large number of laboratory experiments it is 

 :ices«ary to keep a continuous flow. of water through a 

 vessel in' which the level must re- 

 main constant. • Some sort of self- 

 regulating siphon is a great con- 

 venience for this purpQ5,e, and 

 that here described is both simple 

 i 1 construction and very efficient 

 ill use. 



The U-tube, bent out of ordinary 

 (|iiarter-inch quill tubing, • as 

 shown in the sketch, is narrowed 

 at the point A, and the small piece 

 of glass rod, C, is drawn out so 

 as to fit this constriction. The 

 bulb B, sealed on to the top of 

 ll'is rod, floats on the surface of 

 the water. The U-tube must be 

 so fixed that when the water is at 

 the desired level the: rod just fits 

 into A, and so ' closes the exit. 

 If the level of water in the vessel 

 I) rises at all, the bulb is raised, 

 and the excess of water flows out 

 through the siphon. 



W. H. Tait. 



King Edwaid VI., '.5 High School, Birmingham. 



The Plumage Bill. 



The statement has been widely circulated by a section 

 ;of the Chamber of Commerce interested in the feather 

 trade that the aigrettes or ospreys which are now worn 

 are, for the most part, the moulted plumes collected after 

 the breeding season. Ivong ago Prof. Alfred Newton ex- 

 posed this statement. He cmpliatlcally stated that " cast " 

 feathers do not find their way into the market, and 

 added. " I should doubt whether cast feathers have any 

 real value at all in the plume trade," his belief being that 

 no one concerned in it would look at them. Again, Mr. 

 W. H. Hudson wrote : — " Each bird produces only a 

 small number of these valued feathers, and when he sheds 

 them he does not shed them all together in some spot 

 where a feather-hunter will be sure to find them. He 



NO. 2158, VOL. 86] 



drops tnem one by one at odd times, some falling in the 

 water where he fishes, some among the trees and rushes 

 where he roosts, and some are shed when he is on the 

 wing going from place to place." 



Sir E. Ray Lankester, Mr. W. P. Pycraft, and Mr. 

 James Buckland testify to the truth of the foregoing. Sir 

 E. Ray Lankester says: — "It is always the parent bird, 

 slain at the breeding season, which supplies ' ospreys ' for 

 women's hats and bonnets. ... I am quite tired of 

 assuring the public of the facts of the matter." 



In introducing his Bill to prohibit the sale, hire, or 

 exchange of the aigrette and other plumes, Mr. Percy 

 Alden stated that last year some thousands of ounces of 

 these plumes were offered for sale at Mincing Lane. It 

 is estimated that this amount represents the breeding 

 plumes of about 20,000 parent birds, the fledglings of 

 which were probably left to die of starvation. Legisla- 

 tion is the only means of coping with this insensate 

 massacre. Joseph Collinson. 



York House, Portugal Street, W.C, February 28. 



Edward Blyth and the Theory of Natural Selection. 



With reference to Mr. H. M. Vickers's letter in 

 Nature of February 16, I may perhaps mention that the 

 Edward Blyth who edited Gilbert White's " Selborne " in 

 1836, a reissue of which was made in 1858, dated his 

 " advertisement," or preface, from " Lower Tooting, 

 November, 1836." Blyth 's bird notes to this edition are 

 extensive, but the other portions of the book are very 

 free from annotation. Edward A. Martin. 



285 Holmesdale Road, South Norwood, S.E. 



Cat Playing with Shadow. 



Can any correspondent of Nature recall a case of a cat 

 playing with a shadow? 



I know of a cat — a blue Persian — which appears to wait 

 until the morning sun throws the shadow of a cage-bird 

 on the wall of a room, and then seems to play at catching 

 the shadow of the bird as it moves about. 



H. S. G. 



22 Kensington Park Gardens, W. 



THE A-KAMBA OF BRITISH EAST AFRICA.' 



MR. HOBLEV has again put ethnologists in his 

 debt by giving another series of observations 

 on certain tribes of British East Africa. His mono- 

 graph on "Eastern Uganda: an Ethnological Sur- 

 vey," published by the Royal Anthropological Insti- 

 tute in 1902 was followed in 1903 by a valuable 

 paper, "Anthropological Studies in Kavirondo and 

 Nandi," in the Journal of the Institute. In the pre- 

 sent volume he deals mainly with the A-Kamba, who 

 inhabit a large area south and south-east of Mount 

 Kenia, and about whom we have hitherto had 

 extremely little information, with the exception of a 

 capital general and comparative ethnographical 

 account by J. M. Hildebrandt in the Zeitschrift fiir 

 Ethnologie, Bd. x., 1878, p. 347. A small book con- 

 taining vocabularies of the Kamba and Kikuyu 

 languages, compiled by Mrs. Hinde, was published by 

 the Cambridge University Press in 1904, but no 

 details are given about either people. 



The A-Kamba are probably the purest representa- 

 tives of the Bantu stock in British East Africa; they 

 are a sturdy people, the males being about 5 feet 

 6 inches in height. The average cephalic index of 

 ten men is 78"6, while that of two skulls is 74. The 

 nose is platyrhine. Two gen(Mal types of head ar-^ 

 noticeable, one " with very wide massive jaws, curved 

 sides, and tapering towards the forehead, a very 

 coarse negroid type, and the other is, comparatively 

 speaking, a more intellectual type, with a wider fore- 



1 " Ethnology of A-Kamba and other East .\frican Tribes." By C. W. 

 Hobley, CM. 6. Pp. XVI-M74. (Cambridge: University Press, 1910.) 

 Price ys. dd. net. 



