246 



NA rURE 



[December 31, 1908 



The notes on the dilferent plants supply the oppor- 

 tunities for considering accessory problems; thus the 

 scarlet runner introduces twining, the marsh mari- 

 gold leads up to a discourse on marsh plants, and 

 so on. The volume concludes with a short epitome 

 of ecolog^ical principles, while at the end of each 

 chapter searching questions are proposed for solution. 

 The author is to be congratulated on the excellent 

 features of his book, which may be summarised as a 

 clear diction, a logical sequence, and a recognition 

 of the essentials. 



The volume prepared by Mr. Percival Westell and 

 Mr. Cooper does not present any very unique features. 

 It is a systematic book containing a few coloured 

 and numerous illustrations that are quite good, espe- 

 cially those in colour. A preliminary chapter fur- 

 nishes hints on collecting;, after which an explana- 

 tion of general systematic and morphological terms 

 leads to the enumeration of species. The salient dis- 

 tinctions of each order are given, and the specific 

 characters are scheduled at the expense of much 

 space. The book is somewhat simpler than a flora, 

 but less complete, as only about 200 species are de- 

 scribed. 



ELEMEXT.IRY PHYSICS. 



(1) First Year I'hvsics. By Charles E. Jackson. 

 Pp. vii+112. (London: Methuen and Co., n.d.) 

 Price IS. bd. 



(2) Eiujiihruuii in die Eleklrochcmie. By Prof. W". 

 Bermbach. Pp. iv+ 140. (Leipzig: Ouelle and 

 Meyer, 1907.) 



(3) ■'^fngiielisin and Eleciricily and Ihe Principles of 

 Electrical Measurement. By S. .S. Richardson. 

 I'p. viii + 5C)6. (London : Blackie and .Son, Ltd., 

 i()o8.) Price 5.V. net. 



(1) I 'HIS small manual is intended as a first-year 

 -!• text-book for schools where three or four 

 hours per week are devoted to the subject. The book 

 is divided into two portions; the first, theoretical, and 

 consisting of about 100 pages, deals with units of 

 measurement, length, area, volume, density, pressure, 

 and force. The second part consists of 76 laboratory 

 exercises bearing on the subject-matter of the first 

 portion. In addition, examples for home work are 

 given at the ends of each chapter. The book is written 

 in clear and simple language, and the illustrations are 

 good. The section on " Mixtures," p. 51, is ill-chosen. 

 .\ theoretical calculation of the density of a mixture as 

 there indicated will most probably differ from that 

 obtained practically by the pupil, owing to change in 

 volume on mixing. Again, good practical results can- 

 not be obtained from the pendulum experiments if 

 carried out according to the directions indicated on [). 

 85, viz. :— 



" Allow the pendulum to swing through an arc of 

 about 3 in. long and measure the time of 10 complete 

 swings, using a watch with a seconds' hand for this 

 purpose. . . . Repeat taking 20, 30, &c., swings, and 

 froiii each measurement calculate the time of one 

 swing. The result in each case should be the same." 

 ■Again, in section 136 we are told to time 20 swings 

 when investigating the variation of period with length, 

 NO. 2044, \'OL. 79] 



and as an example 1-42 sec. is given as a period cal- 

 culated from such an observation. 



(2) The title of this book is somewhat misleading, as 

 it does not deal with the applications of electric;il 

 methods to chemical industries, but is intended as an 

 introduction to the study of physical chemistry. .Al- 

 though the treatment is of an elementary nature, the 

 book may be profitably read by students of physics 

 and chemistry. The first chapter is devoted by the 

 author to a resume of the laws and principles of elec- 

 tricity ; the second chapter contains the fundamental 

 conceptions and definitions on which the science of 

 physical chemistry is based. The remainder of the 

 book deals with such subjects as the electrolytic dis- 

 sociation theory of Arrhenius, osmotic pressure, con- 

 ductivity of electrolytes, migration of ions, and the 

 theor}' of the voltaic cell. References to more ad- 

 vanced works on the subject are given at the end of 

 the book. 



(3) This text-book assumes a knowledge of the 

 elementary descriptive portions of magnetism and 

 electricity, and is intended for those students who are 

 pursuing the subject further, either as a branch of 

 pure physics or in preparation for a course of applied 

 electricity. The author does not assume more than an 

 elementary knowledge of the principles of trigonometry 

 and mechanics in dealing with the subject. The treai- 

 mtnt, on the whole, is very clear and concise, and the 

 book contains considerably more matter than is usually 

 found in books of this standard. .Solutions of many 

 questions set in recent examinaliims .are incluJed \,\ 

 the text, or given as examples Ui illustrate Ihe subject- 

 matter. These will, no doubt, commend the book to 

 many students preparing for examinations. The state- 

 ment on p. 27, " When the lines of force are parallel 

 the field is of uniform strength," is not a very in- 

 telligible way of defining a uniform m.-ignetic field for 

 an elementary student. Again, on p. (17, " If a con- 

 ductor carrying an electric current is placed in a mag- 

 netic field it is subject to a mechanical force which 

 depends on the length of the conductor, the current 

 strength, and on a measure of the field," is a some- 

 what loose statement, there being no mention of the 

 direction of the field with respect to the conductor. In 

 Fig. 204, on p. 446, " Measurement of Thermoelectric 

 Force," the connections are apparently wrong, 

 although the author gives no explanation of the various 

 parts of this figure. 



OUR BOOK SllELE. 



'I'cxt-book (1/ Physiological Chemistry, in Thirty Lec- 

 tures. By Emil .Abderhalden. Translated by 

 William T. Hall and George Defren. Pp. xiii + 722. 

 (New York : John Wiley and Sons; London : Chap- 

 man and Hall, Ltd., igo8.) Price 21.?. net. 

 WiiRN Prof. .Abderhalden's book was published in Ger- 

 man about two years ago, its general excellence was 

 at once noted, and it stepped immediately into the 

 front rank of text-books which deal with this important 

 and rapidly growing branch of physiology. Its author 

 had already made for himself a great reputation as an 

 original investigator, and as Prof. Emil Fischer's chief 

 lieutenant had done much to elucidate the fundamental 

 question which lies at the root of biochemistry, namely, 

 the constitution of the protein molecule. In spite of 



