34 



NATURE 



[March io, 1910 



author, by effective description and diagrams, shows 

 the asterisms the Great Bear and the Hyades to be 

 but transient phenomena, and the exquisite Corona 

 Borealis but a passing show. New stars, nebulae, 

 and the sun itself next provide material for the 

 author's pen. It will be noticed that the chapters 

 follow, in some sort, an evolutionary sequence. In 

 spite of the temptations of the subject, extravagant 

 and loose statements are rare, though a few have 

 been met in reading. To state that "except for the 

 interference of the moon, we should probably never 

 have known that there is any more of the sun than our 

 eyes ordinarily see " is forgetting that the spectroscope 

 was at least a possibility whether eclipses had occurred 

 or not. Similarly forgetful is the remark that " no 

 instrument now in the possession of astronomers could 

 assure us " that there are planets revolving round other 

 stars than the sun. The statement respecting Mercury 

 that its "average temperature is more than six and a 

 half times that prevailing on the earth " is quite in- 

 excusable. Some attempt at precision in a matter 

 quite capable of being stated clearly is surely worth 

 while. 



In spite of such blemishes the book, as a popular 

 exposition of certain phases of modern astronomy, 

 ranks high. Hypotheses respecting the zodiacal 

 light mystery are clearly set forth, while aurorae, 

 comets, and meteorites are suggestively treated. 

 Chapters dealing with the moon, Mars, and the riddle 

 of the asteroids bring an interesting work to a con- 

 clusion. Some thirty full-page half-tone reproduc- 

 tions of photographs are inserted, most of them being 

 well chosen and excellently reproduced. 



The printing and binding are satisfactory, but the 

 inset illustrations are not securely fastened and are 

 liable to come out. T. F. C. 



WONDER BOOKS OF SCIENCE, 

 (i) The Wonder Book of Magnetis77i. By Dr. E. J. 



Houston. Pp. X4-325. 

 (2) The Wonder Book of Light. By Dr. E. J. Hous- 

 ton. Pp. xii + 349. (London: W. and R. Cham- 

 bers, Ltd., 1909.) Price 35. 6d. each. 



DR. HOUSTON has attempted, in these t\Vo 

 volumes, to deal with the two specified sections 

 of physics in such a way as to render them interest- 

 ing to young people. In order to attain this end he 

 has had recourse to the somewhat novel method of 

 frequently using fairy stories as illustrations. Dr. 

 Houston has had considerable experience in teaching 

 the young, and, therefore, probably knows far better 

 than the writer the kind of treatment of the subjects 

 most likely to appeal to them. But the general im- 

 pression obtained by an adult reader is that the illus- 

 trations are, to say the least, far-fetched, and that it 

 is surprising if children, while sufficiently young to 

 take delight in the fairy stories, can also appreciate 

 the serious parts of the books. We hardly expect 

 to find in the same volume the story of "The Blowing 

 Servant of Fortunio " and the description of Zeeman 

 effect as "the duplication or triplication of spectrum 

 lines when the glowing vapour is subjected to a 

 NO. 2106, VOL. 83] 



powerful magnetic field." Nor is it usual to associate 

 "The Magic Wand of Prince Percinet " with a treat- 

 ment of the colours of thin films and the colour of 

 skylight. 



The parts of the books which actually deal with 

 physics are excellent. The language is generally 

 simple, and the discussion is much more clear and 

 exact than is usually the case in elementary treatises^ 

 Stripped of the fairy stories, both volumes could be 

 read with much profit by grown persons desirous of 

 enlightenment on magnetism and light. The prob- 

 abilitv is, however, that such seekers would be warned 

 off by the juvenile complexion of the work, and thus 

 miss the abundance of useful information contained 

 therein. One further criticism is that some of the 

 diagrams, of which each volume contains a consider- 

 able number, are badly reproduced. This, however, 

 is not surprising when the low price of the books is 

 taken into account. 



With regard to the contents of the separate volumes, 

 that on magnetism contains, besides the usual descrip- 

 tion of the properties of magnets, an interesting 

 chapter on the history of the discovery of magnetism, 

 and another on the possible causes of terrestrial mag- 

 netism. The auroral light and its bearing on the 

 latter is also fully described. The reciprocal relations 

 between magnetism and electricity are clearly stated, 

 and a chapter is devoted to the electromagnetic theory 

 of light. As examples of the less serious side of the 

 volume may be mentioned the chapters entitled " Have 

 Magnets Healing Powers?" and "Magnetism and 

 Magic." 



Among the special subjects treated in the volume 

 on light, attention may be directed to the chapter 

 entitled "The Light Mill," in which Crookes's radio- 

 meter is described, and to those on optical illusions 

 and the effects of persistence of vision. Others are 

 phosphorescence and fluorescence, X-rays and radio^ 

 activity, photography, soap-bubble colours, opal- 

 escence and polarised light. These are all dealt with 

 quite briefly, but, nevertheless, in a lucid and interest- 

 ing manner. 



In conclusion, one may congratulate the juvenile 

 readers upon having these two books so care- 

 fully written on their behalf, and express the hope 

 that some time the author may see his way to pub- 

 lish the volumes in a slightly revised form suitable 

 for older children. 



OUR BOOK SHELF. 



The Periodic Law. By A. E. Garrett. International 

 Scientific Series. Pp. vi + 294. (London: Kegan 

 Paul and Co., 1909.) Price 5^. 



This book may be viewed in two aspects — as a body 

 of information and as a narrative. As a body of 

 information it is very comprehensive. In no other 

 work dealing with the periodic law, so far as the 

 present writer knows, has the statistical information 

 been set forth so fully and discussed in such detail. 

 The author deserves all the credit due to a laborious 

 compiler, and it may seem ungrateful to make any 

 qualification in acknowledging such services. 

 Little seems to have been omitted in the way of 



