Ai'RiL 14, 1905.] 



SCIENCE. 



575 



Her brilliant style of writing is maintained 

 throughout, and is sure to fascinate even the 

 reader who does not fully comprehend her 

 meaning. Sometimes, indeed, her lavish use 

 of synonyms must puzzle those not familiar 

 with the subject; but it carries her and her 

 readers lightly and pleasantly over some chap- 

 ters that would certainly be dry in the hands 

 of most authors. 



The keynote of the book is suggestiveness, 

 as the author points out in the preface, and 

 there could be no better tribute to her success 

 in this respect than the use made of her work 

 by astronomers. She clearly differentiates the 

 known and the unknown, and emphasizes what 

 ought to be found out. 



The book can be commended to the atten- 

 tion of the physicist and the chemist. It is 

 unfortunate that so few workers in the field 

 of chemistry seem to take a positive and active 

 interest in the problems of astrophysics; for 

 in many respects its progress is being delayed 

 while developments are awaited from the 

 chemical laboratories. When these develop- 

 ments come, as when Ramsay solved the mys- 

 tery of helium, the forward movement is 

 rapid. Students of electricity also ought to 

 find considerable of interest in this book and 

 its topics, for our nearest approaches to labo- 

 ratory representations of stellar phenomena 

 seem to be of an electrical character. Yet 

 we really do not know at all how these elec- 

 trical phenomena can be brought into their 

 proper relation to the thermal conditions 

 which doubtless obtain in the stars. 



The work before us is divided into two 

 parts, ' Problems in Solar Physics ' and ' Prob- 

 lems in Sidereal Physics,' the second part oc- 

 cupying something more than two thirds of 

 the volume. The fourteen chapters of the 

 first part deal with the sun's chemistry, and 

 separately with its successive envelopes. Two 

 chapters are devoted to sun-spots, and they 

 sufficiently disclose our ignorance as to the 

 nature and cause of these familiar but no less 

 puzzling phenomena. The last three chap- 

 ters treat of the solar rotation, the solar cycle 

 and ' the sun as a whole.' The author's point 

 of view is the safe and conservative one which 

 has been taught by Young and by Huggins. 



Schmidt's refraction theory of solar phenom- 

 ena is regarded as largely of academic interest. 

 The general reader may safely accept the au- 

 thor's comments as well balanced; and there 

 is no concealment, but rather a frank avowal, 

 of the extent of our present ignorance on the 

 problems of the sun. 



Part II. includes forty-one chapters and 

 enters into the personal details — the vie 

 intime — of the stars, possibly rather too 

 minutely for the general reader. But it is 

 decidedly interesting reading, and the reviewer 

 must confess that the belatedness of this re- 

 view is due to the tendency to peruse these 

 details repeatedly to the detriment of obtain- 

 ing a broad survey of the book. The author 

 adopts a rather simple scheme for classifying 

 stellar spectra and gives to each class a chap- 

 ter. Anomalous and bright-line spectra re- 

 ceive an ample treatment. Spectroscopic 

 binaries and eclipsing stars also get consider- 

 able attention. ' The problem of Beta Lyrse ' 

 occupies a chapter of twenty pages, while the 

 longest chapter is devoted to temporary stars, 

 including Nova Persei. After clusters have 

 been discussed, the nebulaj are taken up in 

 nine interesting chapters, and few of the ob- 

 jects of this class which have been carefully 

 studied are omitted in the author's detailed 

 treatment. A brief final chapter discusses 

 the physics of the Milky Way. 



References to the original sources are faith- 

 fully given throughout the work, and appa- 

 rently with few typographical errors, from 

 which the book is otherwise quite free. We 

 wish that Miss Gierke would adopt the use of 

 the convenient word spectrogram instead of 

 making spectrograph serve for both the instru- 

 ment and the photographic result of its use. 

 Slips of the pen seem to be rare, and there are 

 few points at which a conservative reader 

 would interpret the results of observations 

 very differently from the author. 



The thirty-one insert plates are for the most 

 part excellent. Those printed in the text, 

 except diagrams, are less satisfactory, notably 

 the picture of prominence on p. 104. The 

 light weight of the paper makes the handling 

 of the book a pleasure — and it is likely to 



