JCLY. 1901.] 



KNOWLEDGE. 



159 



fo'.jr limbs — it is more nearly related to the horse than 

 to tho asses. 



The origin and evolution of the Australian marsupials 

 are discussed at some length by Mr. B. A. Benslev in the 

 April number of the Aiiifrirtui Xi/hj-ii/Zx/. In broad 

 contrast to the views of Dr. Wallace, the author is of 

 opinion that marsupials did not effect an entrance into 

 Australia till about the middle of the Tertiary period; 

 their an>-estors beintr probalily ojiossums of the American 

 tyj)e. They -were theu ai-boreal : but they speedily entered 

 upon a rapid, although shortdived course of evolution, 

 during which leaping terrestrial forms like tho kangaroos 

 were developed. The short period of this evolution is at 

 least one factor in the primitive grade of even the most 

 specialized members of the group. In the advance of 

 their molar teeth from a tritubercular to a grinding type, 

 the author traces a curious parallelism between marsupials 

 and placentals. Taking opossums to have been the 

 ancestors of the group, the author considers that Mr. 

 Lydekker may be right in his view that marsupials entered 

 Australia from Asia by way of New Guinea. On the 

 other hand, there is nothing absolutely decisive against 

 their origin being southern. 



In the May- issue of the same journal Dr. H. S. 

 Jennings shows that the spiral revolution of many 

 small swimming organisms is analogous to the revolu- 

 tion on its own axis of a rifle-bullet, namely, in order 

 to render them capable of maintaining a straight course. 



The degi-ee of Doctor of Science has been conferred 

 upon Mr. Vaughan Cornish by the Victoria University, 

 Jlanchester, in recognition of his investigations upon 

 waves and kindred phenomena. 



j^ottcts of Boolts. 



"Adv.vsced Exercises in Practical Physics." By Prof.. 

 Arthur Schuster, PH.D., f.b.s., and C. H. Lee.s, D.sc. (Canibridgt 

 University Press.) 8.s. Illustrated. — It is surely an objection 

 for a book which is to be used in a laboratory to be sent out 

 with uncut edges, and we take this opportunity of .sugge.sting 

 to publishers the desirability of cutting the edges of such manuals. 

 The present book is a laboratory guide for students who, having 

 already had some experience in practical physics, are taking up 

 the subject for the examination for the degree of B.Sc. The 

 course includes seventy-five diiferent exercises, and is therefore 

 fairly extensive. It apparently has been difficult for the authors 

 to know exactly how much " theory " to give in this book as an 

 aid to the working of any particular exercise. Sometimes this 

 aid is unnecessarily full, and at other times too slight. The 

 account of errors of observation is good. The drawings are not 

 very plentiful ; we may suggest one at least which might be 

 useful in a new edition of the work, viz. : The metlu)d of support- 

 ing a specific gravity fla.sk in a water bath by rubber bands. 

 Incidentally we. may remark that the capacity of this bottle is 

 referred to on page 62 as its volume. The account of methods 

 of accurate weighing i* very well done in this section, an<l the 

 mode of entering complicated notes is made clear by several 

 examples. It is noticeable that no use is made of films in the work 

 on Surface Tension. In the experimental work on linear 

 e.xpansion more detail in the drawing of the apparatus would be 

 useful to teachers, who on reading the book will be sure to want 

 to use the method there given. The apparatus for the measurement 

 of expansion of a gas .seems to be very well thought out, ;ind 

 the same remark applies to that used for the latent heat of 

 steam. In the sections under the heading Acoustics, only three 

 experiments are described. The sextant is dealt with at length 

 under Optics, and the great value of the instrument insisted upon 

 — an importajit point for those engaged in arranging practical 

 courses. In the portion of the work devoted to Electricity a 

 very full account is given of the adjustment of mirror galvano- 

 meters. This is sure to prove of great value to the student. 

 Mance's method for internal cell resistance is replaced by Lodge's 

 niodificiition. We confess to liking so much of the contents of 

 this book that regret is felt more has not been included. The 

 standard of accuracy aimed at in the early part of the botik 

 seemed to preface an almost cyclopedic course of practical work. 

 It ia hence with a certain disappointment that we find platinum 



thermometry ilisniissed in a short»note. Notwithstanding this, 

 (he book will be found of great value by both teachers and 

 students. 



"TiiK SelfEduc.^toe in Botany." By E. S. Wisliart, ji.a. 

 ICditod by .fohn Adams, ir.A., ii.sc. (llodder &. .Stoughton.) 

 Illustrated. 2s. 6d. — As stated in a general introductory note, the 

 object of the series to wliich this work is the Uitust ad'rlition, "is 

 indicated by its title, 'The Self-Kducator.' It is hoped that by 

 moans of these books the most isolated student will be able, without 

 oilier aid, to ground liim.self in the various subjects dealt with." Tho 

 tirst chapter deals with giM'miiiation, and is followed by others, treat- 

 ing of root, stem, and leaf. Chapter 6 bears the .somewluifc fanciful 

 title of " Plant life, manners, and morals," and includrs de.t„iiled 

 instructions for carrying o\it cxpirimcntal investigations into various 

 physiological phenomena — some of which are by no means easy 

 when conduchid in a well appointed laboratory, and under the 

 advice of an experienced investigator, and are, we fear, destined 

 to afford little but disappointment to the isolated, unaided, and 

 untrained student. We are told in a section of this chapter, 

 entitled "Intelligence and Sellishness," that many plants " show 

 a sagacity and foresight not. to be despised," as instiinces of which 

 we have the twining of the stems of convolvulus and hop, and tho 

 movements of stamens, the secretion of nectar, and the dehiscence 

 of the ]K)ds of some other plants, and we are further informed that 

 " many instances of scluining and contrivance will thrust themselves 

 upon the observer's notice." ^The author, doubtless, does not intend 

 these expressions to be taken seriously, but it is surely unwise to 

 introduce ideas of this kind, in any form, to the mind of the 

 beginner, by whom the author's light vein may be entirely mis- 

 understood. Further chapters deal with the inflorescence, the 

 flower, and fertilisation and its results. Part II. is concerned with 

 the classification of plants, and although we cannot approve of 

 its arrangement, it. will perhaps be found useful by the student 

 who is not yet familiar with the characters of the natural orders. On 

 the last three pagc'S are given hints to the plant-collector, and the 

 titles of a few useful text-book.s for further study. The author 

 states in his introduction (p. xi.) that "There are many wrong 

 ways of studying botany. . . . But the right method, wh.itever 

 else it includes, must include the principle of beginning in the 

 field, if possible, and, in any case, with actual plants as wholes, 

 and then proceeding to laboratory work." With this sound 

 principle we fully agree, and a book designed to teach the first 

 principles of botany, particularly if it is to justify the title " self- 

 educator," must be written upon these lines, or fall very far short 

 of what it ought to be. Thei-e can be no doubt that the volume^ 

 before us is not prepared in accordance with the view thus 

 expressed hf the author himself. If the author had impressed upon 

 his readers the necessity for constant field-work, and the use of 

 the British or county flora, and had introduced the student to a 

 consideration of luving plants before going into the more technical 

 matter which composes the bulk of his work, we think he would 

 have rendered a far greater service to his readers, and come much 

 nearer to acliieving his own object. The somewhat diagrammatic 

 figures are badly reprodui'ed, but have the excellence — unusual in 

 text-books of botany — of being original. 



" \ Manttal op Elementary Science." " A course of work 

 in Physics, Chemisti-y, and Astronomy, for Queen's Scholarship 

 Candidates." By R. A. (Jregory, f.r.a.s., and A. T. Simmons, 

 B.SC. (Macmillan.) 3s. 6d. — The scope of this book is to a certain 

 extent; defined by the sub-title, but it may be stated at once that 

 the use of the term "work" is fully justified by the contents. 

 Whenever possible, work of some sort js made to precede mental 

 exercise, and as the authors remark, "This is the scientific method 

 — to show that the iirincijiles. rules, and relationships constituting 

 natural knowledge ar(^ records of experience and not matters of 

 opinion." In the sections im Physics and Chemistry, novelties in 

 the way of simple experiments are frequently introduced. While 

 both these sections are admirable, that on Astrcuiomy is of special 

 interest on account of the ))raisi'Worthy attempt which is made to 

 extend laboratory methf)ds in the study of this subject. The 

 student is taught how to a]ipeal to the heavenly bodiis, and if he 

 has no instruments, he is told how to make them. Particularly 

 to V)e commended is the simple form of altazimuth described on 

 ](. 330, though strangely enough the authors have not made quite 

 cle.ar to the student what excellent o))portunities the possession of 

 such an instrument would give him. It is shown how many 

 astronomical |]henomen.i. can be elucidaled by easy experiments, 

 and the use of S()uai'ed |)aper in eoniunction with an almanac is 

 introduced with excellent effect. Work is thus provided for cloudy 

 as well as for clear days and evenings, and if there should be an 

 undue proporlion of the former. tli>' student may profitably occujjy 

 himself in working some of the interesting examples which are 

 liiven. The book is admirablv illustrated, and deserves to find a 

 large circle of students outside the class for which it apjjears to 

 h.'ivr been specially prepared. 



