SCIENCE 



IN. S. Vol. XXVIII. No. 729 



isogeotherms " (with normal temperature 

 gradient) into the lower heds of a sinking 

 geosynclinal prism — a demonstrably inade- 

 quate source of the required heat. On page 

 174 we have : 



Le granite est formg des meines elements ear- 

 aetfiristiques que le gneiss. Plusieurs auteurs 

 I'envisagaient, probablement avec raison, comme 

 le terme ultime du infitamorphisme, et il con- 

 vient peut-etre d'attribuer la meme origine a\ix 

 roehes granitoides basiques, a la syenite, a la 

 diorite, au gabbro, etc. ( ! ) 



In the table of geological periods we find the 

 traditional but inaccurate names " ere Pri- 

 maire " and " ere Secondaire " used as syn- 

 onyms for " ere Paleozoique " and " ere 

 Mesozoique." The " periode Algonkienne " 

 enters the table; it will be interesting to see, 

 in the second volume, what definition a French 

 author can give this expression. For the 

 North American geologist " Algonkian " is 

 hard enough to define ; " Algonkian period " 

 is harder to define. 



In form of publication the book marks a 

 distinct advance over its only rival in the 

 French language — A. de Lapparent's " Traite 

 de Geologie." The improvement is notable in 

 the style of the letter-press and in the intro- 

 duction of many attractive illustrations. The 

 book is marred by the lack of an index — a 

 lack which can not be made up by the in- 

 sertion of a general index in a succeeding vol- 

 ume, for the present thick one should be 

 bound alone. The " Table des Matieres " is 

 placed at the end of the volume, where the 

 index would also be placed if it had been 

 printed. One may hope that some day the 

 French will change their tradition and place 

 the table of contents in the front of the book. 

 Who of us has not wasted precious time 

 searching out the " Table des Matieres " among 

 the appendixes, plates and index sheets of 

 French texts ! 



Reginald A. Daly 



Massachusetts Institute of Technology 



A Text-Booh on Sound. By Edwin H. 

 Barton, Professor of Experimental Physics, 

 University College, Nottingham. London, 

 Macmillan and Co., Limited. 1908. 



There was need of a treatise on sound, 

 which would neither be taken up wholly with 

 a mathematical discussion of djmamical prin- 

 ciples, nor consist merely of experiments, and 

 yet which would so combine these features and 

 so fully cover the subject as to deserve the at- 

 tention and meet the. needs of the serious 

 student of acoustics. Barton's " Text-Book of 

 Sound" occupies such a place. 



It is forty-five years since Hehnholtz's 

 classic, " Tonempfindungen," appeared, and 

 thirty-one since the publication of Lord Eay- 

 leigh's masterly treatise, and in that time no 

 work worthy to rank with these has been pro- 

 duced. The first volume of such a treatise by 

 the late Professor Donkin was published in 

 1870, and this was of the same order as the 

 two works mentioned, but it is doubtful 

 whether it could have appealed to a large 

 number of readers or to any but most accom- 

 plished mathematicians if it had been com- 

 pleted on the lines upon which the initial 

 volume proceeded. 



In the past forty years admirable treatises 

 on heat have appeared, keeping pace with the 

 development of the subject, still more on light ; 

 while those on electricity have been numerous 

 enough and varied enough to satisfy almost 

 every want; but sound as a branch of physics 

 seems to have been side-tracked. Of course, 

 the subject has been included in all eom- 

 pendiums or treatises on general physics, and 

 to these the author acknowledges his indebted- 

 ness. 



Barton's " Text-Book of Sound " is admir- 

 able on many accounts and has little to object 

 to. Indeed all the material in it is excellent, 

 the principal question in regard to some of it 

 being one as to its relevancy. Unless one 

 admits the propriety of including all wave 

 phenomena in the theory of sound it would 

 seem as if some things here were superfluous. 

 Following approved precedents in defining 

 " AcoiLstics, or the study of sound, as that 

 branch of physics which deals with vibratory 

 motion as perceived by the sense of hearing," 

 an adherence to this definition might save the 

 author from the necessity of discussing all the 

 causes and peculiarities of wave motion. Pos- 



