KNOWLEDGE & SCIENTIFIC NEWS. 



[November, 1905. 



Eclipse Shadow Bands. 



During the recent total solar eclipse of August 30 there 

 appear to have been numerous satisfactory observations of the 

 shadow bands, and from the ver>' definite nature of many of 

 the reports now coming to hand, it appears very hopeful that 

 some advance towards the determination of their causation 

 may result. The following notes summarise some of the data 

 supplied : — 



Constantiiu (Algeria). — M.M. Henri de la V'aulx and J. 

 Jaubert, observing at a station about 660 metres above sea 

 level, state that the bands were visible 20 seconds before and 

 after totality : although subject to various irregular move- 

 ments, it was found that on the hori;rontal plane their length 

 was in the general direction — N.E.-S.W. During the shorter 

 intervals of 7 seconds before and after totality a second series 

 of shadows were noticed intersecting the first series, always at 

 an angle of about 25". These had a width of 6 cm. or 7 cm., 

 with intervening clear spaces of 60 cm. or 70 cm. The direc- 

 tion of motion of the bands was regular and definitely deter- 

 mined to be west-south before the eclipse, and in the opposite 

 direction after. 



Tripoli {[iarhary). — M. Lucien Libert observed the bands on 

 a sheet of 25 square metres. They were first seen 6 minutes 

 before totality, and had the appearance of alternate bands of 

 light and shadow, displacing themselves in a direction per- 

 pendicular to their length. They were not absolutely sharp, 

 and at intervals appeared serpentine, as if affected by the 

 wind. The following summary is given of the directions of 

 the bands and their movements: — 



h. m. s. 



239 

 241 15 



25' 



Direction of Bands. 



First series of Bands' N 60" E or S 60° W 

 Second ,, ,. ' N 80" E or S 80'' W 



Third ,, ., N 45" E or S 45 ' W 



S300E 

 S lo' E 

 S450E 



S43<>W 

 S600VV 



REVIEWS OF BOOKS. 



J uolur Course of Practical Zoology, by the late H. M. Marshall and 

 C. H. Hurst ; 6lh edition, revised by F. W. Gamble (London : 

 Smith, Elder, and Co., 1905 ; pp. xxxiv. -|- 490, illustrated ; 

 price los. 6d.). — The mere fact oi a text-book having reached 

 its sixth edition affords such all-sufficient and convincing 

 evidence of its popularity and its fitness for its purpose that 

 any commendation on the part of a reviewer is a mere work of 

 supererogation. Nevertheless we cannot pass over the edition 

 which Dr. Gamble has in so many ways made superior to its 

 predecessors without adding one word of approval to this 

 excellent and invaluable little laboratory manual. In every 

 way it is admirably suited to the needs of the student ; a 

 feature in which it excels so many of its rivals being the 

 specially distinctive type, of various grades, in which the 

 different parts of the structure of each object described are 

 printed. By this arrangement the student is enabled to find 

 exactly what he wants at the moment without any vexatious 

 delay ; and although the arrangement of such details may 

 seem a trivial matter, yet it is one of which only experienced 

 teachers, like the lamented authors of the present work, 

 are able to recognise the full importance and value. Another 

 distmctive feature of the volume before us is the comparatively 

 limited number of the illustrations; and although this may at 

 first sight seem a disadvantage, it is in reality a great merit, 

 since it compels the student to resort to actual dissection, and 

 prevents him from frying to obtain his knowledge at second 

 hand by merely studying figures of the labours of others. The 

 only adverse comment we have to make in connection with a 

 work in every respect admirable, is that we regret the editor 

 did not see bis way to conform to modern usage by substitu- 

 ting the name Braiichwiloma for Amphiuxin. 



Extinct Animals, by E. Kay Lankester (London : A. Constable 

 and Co., Ltd., 1905 ; pp. xxiii. + 331- illustrated ; price 7s. 6d. 

 net). — •• .\ book that tells you exactly what you want to know 

 about animals " was the comment made by a member of the 

 present writer's family after perusing a copy of this profusely 

 illustrated volume ; and as this tribute came spontaneously 

 from one of the " young people " to whom the author specially 

 appeals, it may be taken as satisfactory evidence that he has 

 hit the mark at which he aimed. Professor Lankester is 

 indeed justly famed for his power of imparting information 

 on abstruse subjects in a manner which, while thoroughly 

 accurate and often detailed, yet arouses the interest of his 

 hearers or readers to such a degree that, in place of tieing 

 wearied, they are left with :iu overwhelming desire to know 

 more about the subject under discussion. And as an example 

 of this excellent — and indeed only true — way of teaching, the 

 volume before irs, which is a revised report of a series of 

 lectures delivered by the author before a juvenile audience at 

 the Royal Institution during the Christmas holidays of 1903-4, 

 can hardly be excelled. Whether discoursing on the evolu- 

 tion of the elephant and the marvellous way iu which the jaws 

 of its ancestors were first lengthened to form a kind of 

 '■ bogus " trunk, and subsequently shortened when the real 

 article was developed, or discussing the strange fossil reptiles 

 of South Africa and Russia and their relation to .namiiials, 

 the author is equally succes.sful iu maintaining the interest of 

 his subject and carrying his readers with him. Hig animals 

 apparently have a special fascination for the learned professor, 

 and the reader is introduced in turn to the tliigh-bonc of the 

 mightiest reptile that ever ti'od this earth, to the fossil tooth 

 of a shark beside which the dental weapons of modern species 

 are mere playthings, and to the longest and heaviest elephant's 

 tusk ever put on the London market. Of course, a few holes 

 may be picked here and there by the captious critic ; and we 

 doubt not that in a second edition the author will remove 

 Dimdrodou from the Theromorpha (p. 212), while he will com- 

 pare the tail of an ichthyosaur with that of a shark instead of 

 that of "a fish" (p. 227), and will alter a certain sentence 

 (p. 94), which, to our mind at any rate, conveys the idea that 

 rhinoceroses possess trunks. Such little incidents detract, 

 however, iu no wise from the value and interest of a work 

 which only a man of unusually comprehensive mind and great 

 powers of generalisation could possibly have written, and 

 which will cert.iinly appeal to a much wider circle than the 

 young people for whom it is claimed to have been specially 

 written. 



A Popular Introduction to Astronomy, by the Rev. A. C. Hen- 

 derson, B.D. (T. & J. Manson, Lerwick; 2s. 6d. net). — This 

 little book is exactly what its title implies. It is clearly and 

 popularly worded, and tells just what those who have not 

 made any study of the subject would mostly want to know. 

 And there is no waste of words ; almost every sentence con- 

 tains a fact worth recording, and the facts arc reliable. 

 The book is quite up to date, mentioning Jupiter's 6th and 7th 

 satellites. We can thoroughly recommend this concise little 

 guide to all who wish to gain a grasp of the great science of 

 Astronomy in .•111 hour or two. 



A Technological and Scientific Dictionary. Edited by G. V. 

 Goodchildand C. F. Tweney (G. Newnes). Part X. (Pyr-San). 

 IS. each part. — A good explanatory collection of terms used in 

 science is much needed, and this work, which is gradually being 

 brought out in parts (and will be completed with the 13th), 

 should supply the want. The definitions here given are mostly 

 full and correct, and in some instances, such as under the 

 headings of " Pyrrole," " Radio-activity," " Railways," " Rub- 

 ber," and "Sanitation," articles of several columns are given. 

 But it seems a pity that the line is drawn where it is as regards 

 the classification of subjects to be included. Thus, though 

 such subjects as music, painting, and even heraldry are fully 

 treated of, mil i tary and naval sciences are not referred to ( Range- 

 finders, Rifles, Redoubts, Rockets, Sails and Sailing, <S:c.). We 

 find the dress of the ancient Roman soldier and inedia;val 

 armour described (Sagiiin,Saladc,&c.), but not the equipment 

 or armament of the warrior of today ; rapiers are defined, 

 but not rifles. Various other subjects, too, which might well 

 be included in the term " Technological and Scientific " are 

 not gone into. Several words, such as Uarc/iuliim (of air), 

 l<(/>uliioH (motor), and Riaumiir (ihermometer scale), are con- 

 spicuous by their absence. We must hope that a full appen- 

 dix will be added to include these omissions. 



