June, 1903.] 



KNOWLEDGE. 



135 



very ditiV'i'ent from the glossy green of tlie adult bird. The small 

 number of immature birds points to an enormous death rate among 

 birds of these species in their first winter. Among Gulls the same 

 phenomenon is, I believe, indisputable. At the breeding places in 

 spring there are mature birds in huge Hocks, far outnumbering the 

 young birds which are to be seen, e.g., in harbours. — F. W. Headlet, 

 Haileybury. 



Hoopoe in Sampshire. — On April 2.5th last, wliile taking a walk 

 in the iS^ew forest, Mr. A. D. Sapsworth and myself had the pleasure 

 of watching a Hoopoe. I hare not seen the bird since, and fear that 

 it has met with the same fate as most of the Hoopoes which yisit our 

 southern counties annually. On the same morning, I may mention, 

 in a walk of some three hours we identified i9 species of birds. 



The Arrival of Summer Migrants for 190o. — The following table 

 of arrivals of summer visitors, compiled from various sources, may be 

 of interest. The dates for first arrivals seem generally about the 

 same as other years for the southern counties, but the inclement 

 weather at the end of March and the beginning of April seems to 

 have checked, probably in southern Eurojje, further migration, and to 

 have stopped the birds from spreading northwards in England : — 

 Sand-Martin ... .. March 23 ... Ireland, Wales, and West 



of England. 



r March 22 ... Wiltsliire and Gloucester. 

 House-Martin .\ shire. 



(.March 27 .. Norfolk. 

 Swallow . March 21 ... Hampshire, Gloucester- 



shii'e, and Ireland; 



/March 12 ... Berkshire. 



) March 16 ... Oxford. 



1 March 24 , , . Southern and western 



C counties. 



C ilarch 18 . Hampshire. 

 WUcateai' ...^ March 24 . Southern and western 



(. counties. 



T, T . , (March 21 ... Hampshire. 



^''''^'^'•^ 1 April 21 ... Wales. 



Whinchat .. .. March 20 ... Shropshire. 



Blackcap... ... .. April 5 ... Devonshire. 



Y II -W t '1 C J larch 23 ... Nottinghamshire. 



'' ' " " ^ April 8 ... Gloucestershii-e. 



/March 31 ... Essex. 



) April 7 . Wiltshire. 

 ■" 1 April 10 . . Hampshire. 



(.AprQ 12 ... Suffolk. 



r April 10 . Kent. 

 Cu('koo ... . ..< April 18 . Essex. 



(. April 20 Hampshire. 



,,, T>- i (April 17 ... Surrev and Staffordsliirc. 



IreeP.pit ... \^ ^^^.^^ go ... Wales. 



Grasshopper Warbler April 21 , . Wales. 



T ix'i ■*- i.1 i. (■ April 22 ... Wales. 



I-"^'"' ^^ '"*''*'""°"* Upril 29 . Hampshire. 



Swift ... ... .. May .5 ... Hampshire. 



Wrvneck f '^P"^ ^ •• Hampshire. 



''^^V^^'^^ \ April 12 ... Kent. 



Willow Wren -^ f P"} i^ ' Hampsliire. 



t April 2t> ... Kent. 



Early Nesling of Birds in 1903. — The following records of a few 

 early nes(s may be of interest. The Niglitingale's nest is eitra- 

 ordinary, but I have it on good authority. 

 Nightingale April 18 3 eggs Surrey 



(A. D. Sapsworth) 



Song Thrush March G Fledged young Kent (J. F. Green) 



Feb. 20 Eggs Kent (J. F. Green) 



Robin March 7 Eggs Kent (J. F. Green) 



Haitford Warbler April 20 Feathered young Hampshire 



in nest " (H. F. W.) 



Comhalire Oreen Woodpeckers. — One often sees in the early spring 

 two male Green Woodpeckers engaged in a sort of mock combat over 

 a female. In the Fiehl for April IStli (p. G.54), however, a deadly 

 duel, which was witnessed by " J. E. S," is described. He saw two 

 birds lighting in the middle of .a ]iath. On liis approaching, one of 

 tlie birds (a Green Woodpecker) tlew away , w liile the other bird " lay 

 struggling on the path, severely injured, blood llowin;; copiously from 

 its neck, and in a few moments it died." The dead bird was a male, 

 and its neck was fearfully lacerated, while its tail and other feathers 

 were pulled out. 



All contribuUoiu to the column, either in the way of not£s 

 or photoyraplis, should be forwarded to Harry F. Witherby, 

 at the Office o/ Knowleuoe, 32ti, Hi(jh Holborn, London. 



rbim'bair 



Nightingale 



j^oticcg of BooSg. 



"Spirals in Nature and Art.' By T. A. Cook, with a 

 Preface by Prof. E. Ray Lankester, v.n.s. Pp. xxi. and 20i K 

 (TMurray.) Illustrated. 7s. 6d. net. — At Blois there is a stair- 

 case of peculiar form which there is reason to believe was con- 

 structed between 1.515 and 1520 by a friend of Frangois I. The 

 name of the architect has hitherto been unknown, but 3Ir. 

 Cook gives good reason for believing that the only man who 

 could have designed the staircase was " Leonardo da Vinci, that 

 great Italian artist, mathematician, .scientist and engineer, who 

 died in exile within a few mUes of this very staircase a year or 

 two after it had been begun." The spiral of the staircase 

 appears to be the same as that seen in a section of the rare form 

 of the shell Vohtia i^e.i/ierlilio, in which the helix follows a left- 

 handed instead of the ordinary right-handed curve. Leonardo 

 would certainly have known of this natural spiral ; moreover, 

 he was left-handed, and ninety per cent, of the screws and spirals 

 contained in bis manuscripts are left-banded spirals. These and 

 other facts go to establish Mr. Cook's thesis, and whatever may 

 be the ultimate judgment upon the evidence brought forward, 

 there is no doubt that he has produced a most interesting book 

 which should direct attention to the work of one of the greatest 

 intellects which the world has seen. It is perhaps worth 

 remark that botanists regard the direction in which twining 

 plants climb from above and not from below. The hop and 

 honeysuckle thus climb in right-handed spirals, and the con- 

 volvulus in a left-handed fashion, but Mr. Cook, though familiar 

 with these habits, refers to the two former plants as twining to 

 the left, and the latter as exhibiting a right-handed direction. 

 There are two ways of looking at most things, and this is verj' 

 true in connection with directions of spirals. 



" Papers ox Mechaxicaf. axd PHYsiCAr, Subjects." Vol. III. 

 " The Sui!-Mecuaxics or the Universe." By Prof. Osborne 

 Reynolds, f.r.s. Pp. xvii. and 251. (Cambridge : L^niversity 

 Press.) — An outline of Prof. Reynolds' new theory of the 

 universe was given by him in his Rede Lecture, already noticed 

 in these columns. The present volume contains the detailed 

 mathematical analysis by which the ability of the theory to 

 account for fundamental physical properties is demonstrated. 

 The paper which makes up the volume was read before the 

 Royal Society in February, l'J02, and has been accepted by the 

 scientific world as a contribution of great significance. For 

 many years, the ether — a non-atomic continuous medium per- 

 vading the universe — has been called into being to explain 

 action at a distance. Prof. Reynolds revolutionises this idea, and 

 substitutes for the ether a granular medium having dimensions 

 and properties which he shows are sufficient to satisfy the 

 demands made upon physical theory. In his words this 

 mechanical system " is neither more nor less than an arrange- 

 ment, of indefinite extent, of uniform spherical grains generally 

 in normal piling so close that the grains cannot change their 

 neighbours, although continually in relative motion with each 

 other; the grains being of changeless shape and size : thus con- 

 stituting, to a first approximation, an elastic medium with sis 

 axes of elasticity sj'mmetrically placed." Such an arrangement 

 as this possesses very remarkable properties, and the dilatation 

 which follows from strains caused by local inequalities in the 

 density of the medium completely accounts for poteutial energy, 

 the propagation of transverse waves of light, gravitation, and 

 related facts. Prof. Reynolds has developed a theorj" which 

 will make men of science associate his name with those of 

 Newton and llaxwell. He has loug been recognised as a 

 versatile genius, and his latest contribution to science can 

 justly be described as epoch-making. 



" Comets ani> tiikiu Tails axd the Gegexscuein Light.'' 

 By Frederick G. Shaw, f.o.s., &c. (Bailliere, Tindall I'i Cox. 

 r.tOH.) 2s. Od. — This nicely printed little volume, illustrated 

 with several views of Donati's comet and its orbital jiositions 

 when near the sun,- contains an attempt to explain comets' tails 

 by the passage of the solar rays '' through the gaseous atmosphere 

 surrounding the nucleus of a comet, and thus rendered more 

 vigorous and more capable of being reflected from the meteoric 

 bodies, dust, etc., existing or moving through space or from the 

 sun's atmosphere, if such a matter exists, in the vicinity of the 

 comet.'' This practically constitutes a revival of the old view 

 held by Tycho Braho and others. The author does not appear 

 to have made out a strong case. The peculiar forms displayed 



