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usual elementary account of the phenomena shown by Fresnel's mirrors and by the biprism is given, but

it is supplemented with a simple description of how A TEXT-BOOK OF OPTICS.

to make a pair of very satisfactory mirrors from a

piece of modern mirror glass, or a biprism from some Physical Optics. By R. W. Wood. Pp. xiii + 546.

slips of glass and Canada balsam, and we are told (London: Macmillan and Co., Ltd., 1906.) Price

that “a prism made in this way works quite as well 134. net.

as those supplied by opticians.” THEN a book on optics by Prof. Wood was After a reference to the phenomena of light beats

announced, students expected something and achromatic fringes we pass on to the colours of in teresting, and they have not been disappointed. thin plates and Newton's rings. The section on the In his preface the author explains that when he

polarised fringes produced by two streams polarised commenced his work Preston's “ Theory of Light”

at right angles is very interesting, so too is that on was the only advanced English text-book of modern the preparation of films for the exhibition of Newton's date available. Since that time Schuster's “ Theory colours. of Optics " and the English translation of the late Diffraction is treated at first in an elementary way, Prof. Drude's “Lehrbuch der Optik” have appeared, then by means of Cornu's spiral, and finally, for a and Prof. Wood had to consider whether they covered few simple cases, by means of calculation; the secthe field sufficiently.

tions on the grating may be specially commended. His readers have cause to be glad that he answered In chapter viii. we find an able discussion of the this inquiry in the negative, nor will they regret modern interference spectroscopes, and here again, the fact that he has laid special stress on the experi- both in the case of the Michelson interferometer and mental side of the question, and has devoted consider- of the echelon grating, the experimental conditions for able space to the account of some of his own work. successful working are carefully discussed. The interHis apologies for this are unnecessary; many of the ferometers of Fabry and Perot, and also of Lummer experiments so described are beautiful, and students and Gehrke, are also described. The chapter on learn more from reading a man's account of his own double refraction proceeds on ordinary lines. Stokes's work than in other ways.

verification of Huyghens's law might with advantage While the book hardly claims, perhaps, to be a have replaced that due to Malus, which cannot give complete treatise, it covers a great deal of ground, and

results of great accuracy. In chapter xii., the theory in particular deals with a number of matters, such

of reflection and refraction, the reader is introduced as the laws of radiation, dispersion, fluorescence, and to Maxwell's equations of the electromagnetic field, the optics of moving media, which are not so fully which henceforth become his main guide in the theotreated in some other recent works. A student com

retical part of the book, though the theory of dismencing the study of optics would perhaps hardly persion is in the first instance developed on the lines begin with this book; he would find, however, in its of the work of Sellmeirr and Helmholtz. pages when he came to read them some most in- With regard to optical theories generally, Prof. structive views of the subject. The earlier chapters Wood has from the first adopted the view put fordeal with the rectilinear propagation of light and its

ward by Schuster in the preface to his recent book reflection and refraction. They gain much by the on optics. photographic reproductions showing the passage of a wave of sound through an aperture, and after reflec

“So long as the character of the displacements

which constitute the waves remains undefined we tion and refraction at a plane surface, and teachers will do well to insist on the utility of the graphic

cannot pretend to have established a theory of

light.” method of studying the changes in wave form, which Prof. Wood uses freely.

In dealing with the theory of reflection and refracThe theoretical treatment of the matter is perhaps tion, the importance of the part played by surface less satisfactory; it is based essentially on that of

films is duly noted. From this point onwards the Verdet. Schuster's paper on the method of analysing interest of the book becomes greatly increased.

An in an elementary manner the propagation of a plane admirable account is given of recent work, much of wave might with advantage have been alluded to. it due to the author, connected with dispersion and In dealing with both reflection and refraction, absorption, especially the anomalous dispersion of Fermat's law of minimum time is explained at an sodium vapour. The optical properties of metals are early stage, and afterwards freely utilised.

developed on the electromagnetic theory, and reference A special point in these early chapters is made of is made to the important work by Rubens and Hagen, the refraction of light by media of varying density, and who showed that many of the discrepancies between the results are used to illustrate and explain the theory and experiment noted by other observers arose phenomena of mirage. Prof. Wood's arrangement from the employment of waves of too short length in for producing mirage on the lecture table is well the investigation. worth notice; so too are the experiments on anomalous After some account of rotatory polarisation, we come dispersion, and especially the very beautiful one for to the chapter on magneto-optics. The theory is showing the anomalous dispersion of sodium vapour. worked out according to the two lines indicated by We come next to the interference of light. The Drude; the first hypothesis is based on the existence

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of molecular currents in the median streams of struck some unseen object, sprang a leak, and only revolving electrons the motions of which are acted reached Galle Harbour just in time to escape sinking. upon by, and react upon, the magnetic forces of the Her passengers were then transferred to the Polyimpressed field, while the second hypothesis is that nesien, on which they continued their voyage from of the Hall effect, in consequence of which an electron Colombo, and arrived, after a further mishap in the thrown into vibration in a magnetic field experiences shape of a breakdown of the engines, at Saigon. a force depending on its own velocity and on the From this town, with the beauty of which Dr. Doflein strength of the field. The results of the theory are was more struck than with its morals, he travelled by applied to the discussion of the magneto-optics of Hong Kong, Macao, Canton, and Shanghai, where sodium vapour, taken from a paper by Prof. Wood he heard of the defeat of the Russian feet and saw himself, and also to an explanation of the Zeeman the interned Askold in dock, to Nagasaki, and thence effect.

by Yokohama and Tokio to Sendai Bay, in the Chapters on the laws of radiation, the scattering of Rikuzen district on the east coast, where his works light, the nature of white light, and the relative was to begin. motion of ether and matter conclude the book. In The reason which had led Dr. Doflein to choose connection with this last subject, Prof. Wood points this locality for his investigations was that on the out that all experimental evidence, with the excep- east coast of Japan the warm current known as the tion of the well-known Michelson-Morley experiment, Kuro Siwo, or Japan coast current, derived from the is in favour of the hypothesis of a stagnant ether, and north equatorial drift, meets the cold Kurile current that the only explanation of this discrepancy, so far from the north on more or less equal terms, and that

we can see at present, is that due to Fitzgerald therefore in this region the relations of the Indoand to Lorentz, that a change is produced in the linear Pacific and northern faunas might best be studied. dimensions of matter by its motion through the ether. On the western side of the islands the Tsushima

Sufficient perhaps has been written to show that current, an offshoot of the Kuro Siwo, appears to Prof. Wood has placed students under a considerable have little influence on the temperature of the wiitti, debt by the publication of this book, while the pub- which, so far as is known, has here a more prelishers are

to be congratulated on the manner in | dominantly subarctic fauna. The result of the inwhich they have produced it.

vestigations at Sendai was to show that there is no sharp boundary between the southern and northt in

faunas, and there is evidence that the change from RESEARCHES IN JAPANESE WATERS.

the one to the other is gradual, and takes place all Ostasienfahrt: Erlebnisse und Beobachtungen eines along the east coast of Japan. This is probably due

to the fact that the two currents interlace in a comVaturforschers in China, Japan, und Ceylon. By Dr. Franz

plicated manner and change their position with the Doflein. Pp. xiii + 511. (Leipzig :

time of year.

Our knowledge of these currents is Teubner, 1906.) Price 13 marks.

largely owing to the work of the unfortunate Admiral DR; R. DOFLEIN adds one more to the long list of Makaroff, who perished off Port Arthur. Dr.

books which have been written to give popular Doflein's stay in Sendai was brought to an end by accounts of scientific expeditions. In the year 1904 he bad weather, and he then left for Sagami Bay in the undertook a journey to the Far East for zoological south, where he made his headquarters at Aburatsubo purposes, and particularly with the object of investi- in a small marine laboratory belonging to the Unigating the fauna of Japanese waters, which is of versity of Tokio. peculiar interest, not only as possessing remarkable The fauna of Sagami Bay is extraordinarily rich. forms of its own, but as containing an admixture of probably on account of the abundant food supply genera belonging respectively to the cold northern owing to the mortality among the surface organisms seas and to the Indo-Pacific region, which meet in of the two currents in consequence of the change of that locality, with a large deep-sea ” element. In

temperature when they meet. It has been collected the book before us we have a record of the obsery

by many naturalists from von Siebold onwards, and ations and results of this voyage, and of the impres- Dr. Doflein wisely gave his chief attention sions made on the traveller by the countries he passed much to collection as to the observation of the habits through

and mutual interdependence of the animals, both of The outward passage was an eventful one. In the deep and shallow waters. He describes his the Red Sea the Prinz Heinrich, on which Dr. impressions of the latter in a graphic chapter, and Doflein had left Naples, was stopped and searched by makes some interesting remarks on the meaning of the notorious Russian auxiliary cruiser Smolensk, their coloration. There seems to be a large tropical and the mails were taken from her. The incident element, brought, no doubt, by the Kuro Siwo. After was made more exciting by the presence on board of some weeks' investigation of the shallow-water tauna. high Chinese and Japanese officials, and created con- Dr. Doflein returned to Tokio to hire a small steamer siderable commotion in Europe at the time. Further for deep-water work. The first vessel that he trouble, however, awaited the Prins Heinrich. Off chartered sank off Misaki, near Jburatsubo, and Dondra Head, in a heavy sea which would probably thus wasted precious weeks of fine weather, but with have sunk her boats if they had been launched, she another he was able to do good work, both on the

not so tater.



plankton and on the ground-fauna at various depths intention of his handbook is to supply as plain and down to about 900 fathoms. Much material was also simple a means as possible for the identification of obtained for him by Japanese deep-sea fishermen with those birds, and their nests and eggs, which are to be * Dabo " lines.

met with in the inland districts of this country, and In summer the warm Kuro Siwo waters cover the are therefore more likely to cross the path of the surface of Sagami Bay, but in winter the north-west greater number of persons interested in bird life. winds bring down the cold current to overlie it, so Knowing his birds thoroughly well, the author has that the self-registering thermometers reveal a layer written most charming and interesting accounts of lof warm water between two cold layers. In this them, and his long experience of them in the field marm layer the fauna of the Kuro Siwo is found, has enabled him to introduce into his sketches much while the surface layer has a very different and largely of the individual character and temperament of each yogetable plankton. Is has been said, there is great species—those little peculiarities a knowledge of which ortality among both these sets of organisms, with is only to be gained by long acquaintance, and by the result that the ground-fauna at all depths, from which the old hand knows his birds at a glance or vide-marks downwards, is extraordinarily rich. The by a note heard in the distance. When the object is bruken nature of the sea-bottom, providing a greatly to teach the beginner in the study this intimate knowincreased surface and variety of habitat, no doubt | ledge is very necessary, and all birdmen (who will coitributes to the same result. Another peculiarity read the book for the pleasure it will give them) will of the fauna of Sagami Bay is the appearance in very recognise and appreciate the happy touches of demoderate depths, of sometimes as little as fifty scription which arise from it. 1.1thoms, of forms which have usually been found As the book will, we think, be in some demand, considerably lower, at 500 fathoms to 1500 fathoms. we offer a few suggestions in view of another edition. Doflein accounts for this partly by the suitably low To give the salient features of the general appearance buttom temperature, but more by the stillness of the of a bird as seen at a little distance should not be

Many of the so-called deep-sea forms are, he difficult, but the descriptions here, in many cases, -29%, more properly still-water forms, specially adapted

be hardly sufficient. The fieldfare, for absence of motion rather than to the other peculiar instance, is merely differentiated from the missel conditions of the deep sea, and their vertical range thrush (in plumage) as having a more distinct grey could probably be found to be considerably greater patch on the lower part of the back; whereas its wire the same attention to be paid to the exploration greyish head, rich brown mantle, and the blue-grey of intermediate depths that has been given to the of the patch on its lower back (from which the bird investigation of the shore-belt and the deep sea. This is sometimes called the “pigeon felt) might have surmise appears extremely plausible.

been pointed out as sufficiently apparent to serve as Bad weather and accidents to his apparatus brought identification marks. The short wings of the sparrowihe investigations once more to a standstill, and Dr. hawk might have been alluded to, as well as the Doficin left Japan. On his way home he stayed in

want in the cirl bunting of the bright chestnut rump Ceylon, and he gives an interesting account of his so conspicuous in the yellow hammer; the distinctly researches on fungus-growing termites there. Some colder tints easily seen in life of the marsh compared remarks on the spinning ant Ecophylla bring the with those of the reed warbler, and the streaked under book to a close. We have read it with great pleasure. parts of the adult Montagu's harrier are merely further The scientific portions are in places very suggestive, instances of the kind of recognition marks we wish the chapters on the ways and customs of various to indicate. countries, and especially of Japan, are bright and As the book is intended for readers whose knowittractive, and the numerous illustrations are often ledge of ornithology is of an elementary character, really beautiful.

L. A. B. something more about the plumage of the chaffinch

than the statement that the hen bird is a good

deal duller than the cock is desirable, and the want BIRD BOOKS FOR BEGINNERS.

of it is all the more felt, because the following Handbook of British Inland Birds. By Anthony semble the chaffinch, and is described in comparison

species, the brambling, is said rather closely to reCollett. With coloured and outline plates of eggs with it. The whitethroat is described as if it were by Eric Parker. Pp. xix + 289. (London : Mac

uniformly coloured on the upper parts, whereas the millan and Co., Ltd., 1906.) Price 6s.

greyish head contrasts with its rufous-brown back ; 4 Pocket-book of British Birds. By E. F. M. Elms.

and as

we are dealing with birds seen at a little Pp. viii + 150. (London : West, Newman and Co., distance, it would have given a better idea of the cock 1906.) Price 25. 6d.

stonechat to say that he had a black head than that IF F in these days the way is not made smooth for he had a conspicuous black patch on the throat and

the young ornithologist it is not for lack of books face. We should not have said that the pied flywritten in his interest. Mr. Collett thinks that there catcher had the appearance of being of slender build, should be a useful place for a book in which the space

we detect that the eggs of the whinchat are gained by omitting the sea and shore birds is devoted usually a good deal greener and deeper in tint than 10 a closer account of the inland species, and the chief ordinary hedge-sparrows' eggs. The author thinks

nor can

The "



that the notion that the mistletoe thrush haunted apple Newman's “ Bird-nesting and Bird-skinning," wh'' trees for the sake of eating mistletoe berries, and is of the same size and issued by the same publisher hence got its name, is not confirmed by the bird's and contains full particulars of the nests and ega actual habits; but we have it on the authority of our Some of the observations on bird language, the greatest living ornithologist (an opinion based on on some of the gulls and terns, for instance, do n. personal observations) that the connection of the bird appear to be altogether satisfactory, but this hard with the mistletoe is no figment, as some have tried little volume (which is furnished with a good inde i to maintain, and that this thrush is exceedingly fond cannot fail to be of great service to the student of the luscious viscid berries of the mistletoe.

field ornithology. While fully allowing that the attempt to put a bird's note into syllables is in most cases a failure (so far as

A GUIDE TO BRITISH DIPTERA. people in general are concerned), there are exceptions, and it would surely have been desirable in the interests A Preliminary List of Durham Diptera, ai!, of the young field ornithologist to give in words as

Analytical Tables. By the Rev. W. J. Winga'r many of the more remarkable bird-notes as lend them

Transactions of the Natural History Society selves to this treatment.

you-tick ” of the

Northumberland, Durham, and Newcastle-upt. whinchat and the “twit me-dick” of the quail (from

Tyne. (New Series.) Vol. xi. Pp. vii+ 410; uit which the birds take local names), the “hweet-tit

seven plates. (London and Edinburgh: Williar. tit” of the redstart and the “ chuck-chucka " of the

and Norgate; Newcastle-upon-Tyne : F. and 11 red-legged partridge, are a few cases in point. But

Dodsworth, 1906.) Price gs. to take the case of the curlew as here treated,


'HE author, or, as he would probably prefer to mention is made of the fact that some of its varied styled, the compiler, of this excellent manu. cries have suggested names for it, and the remark has done himself less than justice, for if, instead that “the cry recalls some of the notes of the plover, the modest title associated with the name of a sir ! but is far more free and powerful,” hardly seems to English county, he had chosen some such designati convey an adequate idea of the curlew's characteristic as that at the head of this notice, he would mun. cries. We wonder if the song of the lesser white accurately have expressed the scope of his work a' throat would strike most people as mo quiet and would also, perchance, have brought the latter to the unobtrusive" than that of the whitethroat.

notice of a wider circle of readers. The descriptions of the nests and nesting habits are Little by little budding entomologists in this counts: especially successful, and will be most interesting to are beginning to realise that butterflies and maits experienced bird-nesters, as well as useful to the novice. and beetles are not the only orders of insects wort“; The coloured figures give, on the whole, a good idea of of study, and the number of those who devote th: the eggs, although some of the plates suggest three-energies to the flies, or Diptera, though still small bus colour printing, and that one colour has obtained un- comparison with that of the students of the itiro due prominence. White eggs are merely figured in popular orders, is steadily increasing. As Mr. W. outline, and the artist has succeeded in representing gate truly remarks in his preface, no other order: the characteristic shape of average specimens. An insects" has so many interesting and varied f. index, which is all that can be desired, and a classi- histories, and none so deeply affects the human fair fied list of breeding species and regular visitors make whether as protectors when acting the parts reference to the different species easy; but we cannot scavengers, or depredators destroying the crops, ' understand the application of the note to the latter, scourges carrying the deadly micro-parasite." L. that the visitors are distinguished by italics, for we fortunately for the beginner, the bulk of the literatur find very few names so treated, and among them those dealing with European Diptera is in foreign tonglets of both the yellow and the grey wagtails.

chiefly German, and, Walker's “ Insecta Britanrica Mr. Elms's thin volume, which slides so easily into being hopelessly inadequate and out of date, it has the pocket that there is no excuse for leaving it hitherto been impossible to satisfy the natural behind on a field day or omitting to take it out every of the novice for a work in English that, while sup: morning during the migration seasons, is intended | ing an outline of the structure and classification solely for the purpose of reference in the field. All Diptera, will at the same time provide the means for our British birds (properly so-called) are included, the the identification of the bulk of the British represemi rare and accidental visitors or stragglers to our shores atives of the order. The basis for all work uit hardly coming within the scope of the book, as the British Diptera is, of course, Verrall's “ List," the chances of seeing them during a country ramble are second edition of which was published in 1901. 1: very slight. A vast amount of information has been this are the names of 2884 species, and when it is included in the small compass of this pocket-book; the added that Mr. Wingate's tables, which are chic, plumage, period of residence in this country, language, derived from Schiner's classical work on the Diptera habits, haunts, and food are all treated concisely under of Austria, furnish characters for the determination w their several headings, as well as some particulars of no fewer than 2210 of these, it will be seen that the the nidification; but in the last respect it is pointed present volume should go far towards supplying the out that the present volume is intended to be used British student with precisely the aid that he requires and carried in conjunction with the new edition of In addition to those already mentioned, details je

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also given of a number of species either identified as

OUR BOOK SHELF. British since the appearance of Verrall's “ List,” or Illogical Geology. The Weakest Point in the Evoluwhich may ultimately prove to be so, with the result tion Theory. By George McCready Price. Pp. 96. that " characters more or less satisfactory are given (Los Angeles, California : The Modern Heretic inr 2526 species," with “ localities for 626 of these " Company, 1906.) Price 25 cents. which Mr. Wingate has himself collected in the The author of this book proposes to collect the county of Durham during the last ten years,

opinions of his readers, and a printed form is appended Turning to the actual contents of the volume before doubt that a writer so much in earnest will make

on which comments may be recorded. There is little us, we find that, after a couple of pages on collecting some modifications in his next edition as the result of and preserving, eighteen pages are devoted to a friendly criticism. But geologists who have taken ynopsis of the external morphology of Diptera in the the pains to base their conclusions on hard work and form of a description of a “ Fly Chart” (Plate i.) or

study in the field, and not on the perusal of each diagram of a hypothetical Dipteron, so arranged

other's text-books, will remain unsatisfied with Mr.

Price until he also has undertaken a course of geoto display all or most of the characters used in de logical observation. In his introduction he offers a scriptions. This is followed by an analytical table

munificent sum to anyone who will “ show [him] how of families, which occupies ten pages, and the re- to prove that one kind of fossil is older than another." mainder of the book, with the exception of a few It is not until we read his book that we perceive the pages of addenda and indices, consists of tables for intellectual difficulty of accepting this sporting pro

For Mr. Price believes (p. 20) that the determination of genera and species. · In addition position.

geologists assume that in the long ago there were to the fly chart, which we think would have been

no such things as zoological provinces and zones”; clearer had the shading been omitted, characteristic he believes that (p. 30) the inversion of stratified destructural details, such as antennæ, wings, legs, &c., posits is nowhere proved by physical evidence; that :re represented in the six following plates.

(p. 46) there are “ numerous families" of molluscs So much care and thoroughness have evidently been and brachiopods which disappear suddenly and com--xpended upon this work that there is little room for pletely with early Palæozoic times, and yet are found

alive now in our modern world; and that (p. 68) the criticism of any kind; a few minor emendations may,

custom of classifying the Tertiary strata by the however, be pointed out. On p. 198 attention should relative percentage of living and extinct forms that have been directed to the vertical stripes of longer they contain is “utter nonsense." If Mr. Price hair on the eyes of the common drone-fly (Eristalis would join one of the field-parties from some American tenax, L.), which are an easily recognised and dis- university, he would soon find that his quarrel must


be with natural phenomena, and not tinctive feature of the species. Speiser's name

, l'arichæta is used (pp. 212, 228) for the preoccupied imaginary hierarchy of illogical geologists.

G. A. J. C. Erigone. Rob.-Desv., instead of Ernestia, Rob.-Desv., which Bezzi has recently shown to be the correct

The Religion of Nature. By E. Kay Robinson. Pp.

xii +215. (London: Hodder and Stoughton, n.d.) designation. It should be noted that E. strenua,

Price 3s. 6d. Mg., is a synonym of E. rudis, Fin. The life-history

MR. ROBINSON has written a book that is sure to of Lipara lucens, Mg., is not " unknown," as stated

interest a large number of readers. His object is to 00 p. 361; the larva mines in the heads of reeds.

show that there is no cruelty in nature, that animals The Phoridæ (p. 383) are placed in their time-honoured are not self-conscious, and, therefore, that such pain position among the Cyclorrhapha, following the as they feel is not pain of the kind that human beings Borboridæ (as in Verrall's “ List " of 1901), though,

are familiar with. It is only “the natural bodily as shown by Osten Sacken, the true affinities of these

protest of a living organism against injury”; and

since there is for animals only this painless pain, and sery aberrant Diptera would appear to be with the

since their cruelty is not really cruel, there is in Orthorrhapha, the more primitive of the two main

nature nothing antagonistic to the principles of redivisions of the order. The bionomic notes on the vealed religion. -trange-looking Hippoboscidæ (pp. 394-5) lack some- No one who knows anything about animals can thing in precision : Hippobosca equina, L., stated to

fail to realise that their capacity for suffering is much be" parasitic on quadrupeds, especially horses," is exaggerated by extreme humanitarians. A highly

bred pigeon will undergo an operation for hernia a parasite of horses and cattle; Lipoptena cervi, L., apparently without feeling it, and directly it is over also described as parasitic on quadrupeds," is found will begin quietly to eat his Indian corn. Animals on red and roe deer; Stenopteryx hirundinis, L., so do not suffer in anticipation, they do not brood over far as the present writer is aware, is met with on the past, and the actual torture, as everyone knows, Soung house-martins, not on young

“ swallows”;

is often far less than the picture of it that haunts the

mind before and after. Let us hope, therefore, that and Oxypterum pallidum, Leach, is a parasite of the

all unreasonable humanitarians will read this book. wift, not of the swallow. As already stated, how- In the opinion of the present writer, though Mr. mer, these are details of minor importance. By the Robinson fails to prove his main thesis, yet he makes it publication of this work Mr. Wingate has earned the clear that the sufferings of animals as compared with gratitude of all who are interested in British entom- those of men are as moonlight to sunlight. In fact, ology, and it is to be hoped that, as the result of his distinguished from short spells of pain.

the human race has almost a monopoly of misery as labours, he may have the satisfaction of witnessing

We can only very briefly trace Mr. Robinson's line a considerable accession to the ranks of British

of argument. A sensitive plant behaves as if it had dipterists.

E, E. A. feeling, but, being a vegetable, it cannot feel. A sea

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