August i8. 1910] 



NATURE 



The subject is to be treated from the technical as well 

 .1-. from the theoretical standpoint, and is to be made 

 intelligible to a bejjinner without forfeiting its char- 

 acter of a complete text-book and work of reference. 



Part i., after a short history of the development of 

 metallography, deals with the "nature" of metallic 

 alloys, the application of the phase-rule to the con- 

 sideration of the various types of freezing of binary 

 alloys, and also with solid solutions and chemical 

 compounds of two metals. The remaining fourteen 

 pages of the first part and half of part ii. deal with 

 the " Zustandsdiagramme " of all the possible binary 

 alloys of the metals manganese, iron, cobalt, nickel, 

 copper, silver, gold, palladium, and the metals of the 

 platinum-group. The second half of part ii. is devoted 

 to internal kinetics, embracing such subjects as crystal 

 growth and transformation, diffusion in metals, &c. 



Whether all the objects aimed at will be achieved 

 by the author cannot be predicted from a perusal of 

 the first two instalments, but it may be safely asserted 

 that a very promising beginning has been made on 

 what can truly be described as a colossal task. The 

 subjects already discussed are treated clearly and in a 

 masterly style, and the arrangement (which is a matter 

 of great importance in metallography) is excellent. 

 The work will constitute the only complete text-book 

 on the subject, and will undoubtedly rank as a classic. 



EXERCISES IN PHYSICAL GEOGRAPHY. 

 (1) Manual of Physical Geography. By Dr. F. V. 



Emerson. Pp. xvii + agi. (New York: The Mac- 



millan Company; London. Macmillan and Co., 



Ltd., 1909.) Price 6^. net. 

 {2) .1 Laboratory Manual of Physical Geography. By 



Prof. R. S. Tarr and O. D. von Engeln. Pp. xvii + 



36'. (New York: The Macmillan Company; 



London : .Macmillan and Co., Ltd., 1910.) Price bs. 

 ( I ) ' I "■ 1 1 E purpose of the first of these books would 

 ->- have been made clearer if it had been entitled 

 ■■ -Manual of Exercises in Physical Geography," for the 

 273 pages of which the body of the book is composed 

 are almost entirely made up of questions and direc- 

 tions to students. The manual is divided into eighteen 

 chapters, the first on the earth as a planet, the next 

 four on climate and others on common minerals and 

 rocks, on the contour map, on weathering streams 

 and stream valleys (a long chapter, in which promin- 

 ence is given to the cycle of erosion and all that that 

 involves), on land forms (three chapters), on glacia- 

 tion, lakes, the ocean, shore lines and forms, harbours, 

 and soils, the final chapter being devoted to studies 

 of typical areas. 



Now there can be no doubt that teachers of the 

 subject could hardly fail to get many a useful hint 

 from an examination of this volume, but, on the other 

 hand, it is scarcely conceivable that any teacher, at 

 least in this country, would ever try to make use of 

 it as it stands. For this there are several reasons. In 

 the first place, the manual is not self-explana- 

 tory. Among the questions of which the bulk 

 of the book is made up. some are childishly 

 simple (though, it may be admitted, not without justi- 

 NO. 2129, VOL. 84] 



fication in the author's way of presenting his subject), 

 Others assume that the teacher is well versed 

 in his subject, and has either alreadv given the neces- 

 sary explanations to his students or is prepared to do 

 so when the student is required to answer them. Some 

 of the questions are, unfortunately, confusing and 

 misleading. Moreover, the teacher who is sufficiently 

 well versed in his subject to be able to use the book 

 will be too independent to submit his mind slavishly 

 to the lead of another in presenting the subject to his 

 class. The author says that the exercises have for 

 the most part grown out of his class-room experiences, 

 and it may fit in very well with the rest of the 

 author's teaching of the subject, but it is not likely to 

 fit in with the method of anyone else. Finally, the 

 exercises set in this volume must involve the consump- 

 tion of a great deal of time, and the doubt cannot 

 but suggest itself whether the result in trained in- 

 telligence will be at all proportionate to the amount 

 of time and labour expended. 



(2) The work by Prof. Tarr and Mr. von Engeln is 

 similar in design to that of Dr. Emerson, and its 

 distinguishing features may be best given by the 

 following extracts from the preface : — 



"The feature which will first attract attention is 

 the leaving of space after each question for the 

 student to write the answer. This serves a double 

 purpose. It ensures the student's following the argu- 

 ment of the outline and the appreciation of every point 

 by personal observation and deduction ... 



" Another feature which we feel sure will meet with 

 general approval is the insertion of all maps, figures, 

 diagrams, and tables at the exact place where they 

 are needed." (These maps, &c., it should be stated, 

 are all likely to be very useful.) 



The authors claim, moreover, as the most marked 

 pedagogical departure in their manual, their orderly 

 method of presenting the physiography of the lands. 

 We may note further a feature which is likely to 

 attract attention even before that just mentioned. 

 The loose-leaf construction of the manual makes it 

 a very simple matter for the teacher to change the 

 order or introduce other work. The pages are all 

 perforated to allow of their being detached, and pierced 

 with two large holes to allow of their being refixed 

 in another arrangement, this being done because 

 " the authors feel that teachers who are progressive, 

 capable, and enthusiastic over the subject should be 

 given the greatest latitude in carrying out their own 

 ideas." 



Finally, with reference to the present reviewer's 

 remark at the end of his notice of Dr. Emerson's 

 work, it is only fair to say that the methods of this 

 manual, 



"are not to be regarded as experiments. The senior 

 author has had over fifteen years' experience and the 

 junior author four in the ' laboratory teaching of 

 physical geography." 



They tell us, too, that the results in their own 

 classes have been very gratifying, and that the 

 students pursue the work with keen interest. The 

 reviewer, therefore, would have his "doubt" taken as 

 no more than a doubt, and he is sure that such sys- 

 tematic efforts towards the improvement of teaching 

 are entitled to svmpathetic consideration. G. G. C. 



