2IO 



NATURE 



[April 13, 1911 



Though the book contains very little that is original 



either ill m;iMci- < n- arrangcnK-iit (niiir-,^ in ii- s|)«'cial 

 .•i(i:i|.t;ilii'n to ilif syllabuses m1 M-ii.iin < \.iiirmin|^ 



bodies), iliep- i-,, (.11 the iillier li;in<i, nniliin:; uliicli 

 rrills ti.i .iii\ii-.i' (I iii( i-iii. Tlie l.il.di :iti.r\ (.pe|-;i- 

 tidii^ .111 sneli ;is li:i\e ,i|)|h ,imn1 in h.iU ,i d. ./' n Ih-mUs 

 on liie sulijiil. '1 he\ 

 and illu^-lialed 



U\ 



. V,. T. Druer\ 

 .(-•d^c and Son- 

 . and Cu., n.U.> 



tainin^ 

 prelim ii 



Univfi'sii \ . \\i- 

 author in advisin 



'1 h(\ .-lie rle.ii 1\ .111(1 lulls (!' -( I ihed 



'lliei.- i-, al-u a ii-i-lui appendix cun- 

 lariical uurk ])r's,nli'd I"!' llie 

 < xaininalion, part ii. , <il LdndnU 

 shdulil Ik- \eiy v.in\- In foUow the 

 Indents wishim; i^ cai'ry the sub- 

 jerl furilier lo niak<' an extended -tud\- of Lassar- 

 Colm'-s •• Arbuiti.nietliiiden " <m- Me3'er'.s " Konstitutions- 

 ennittelung," both of iIm m ponderous and useful, but 

 incomparahlv dtdl and loi inidaf)lr, books of referonrc. 

 Apart t'rdni this the hook may be s;iiily recommended 

 to all students of practical organic chemistry. 



{:.) Dr. Knocht has collected in the form of a small 

 mon(it;rai)h his various papers on the use of titanous 

 chloride a^ a volumetric reagent. His method is so 

 well kiiduii .1111.. p.l; anal\'^is, .md especially colour 

 chemi^i-, .i^ It) require no description, and its value 

 h.i^ heen fully recognised. The present volume should 

 ser\<' te extend ils use by l)rini.^ing it to the notice 

 of a larL;er puhlic, and h\' emphasising' its remarkably 

 wide aiijdicalion. Titanous sails, it mav be added, 

 are readily procurable, so tliat tlierc is no obstacle 

 in the w;iy td' their emplox'ment. 



(3) " Cest Ic ])remier pas qui coute " is probably 

 truer of text-books of chemistry than of other 

 sciences. It is because authors will assume that 

 chemistry is an exact science and that its principles 

 are capable of precise definition that the opening 

 ( hapters are frequently so unsatisfactory. To begin 

 with d(dlnitions and LM-ner.alisations is to court con- 

 tradictions .and inciiusisiencies at every turn. Here 

 we ha\e a volume by an obviously thoughtful and 

 car(dul writer who attempts to define chemical and 

 physical change. "These [physical] properties are 

 alwavs the same in all specimens of the same sub- 

 stanc( , whatever its source, when they arc examined 

 under the same condition," yet a few paragraphs 

 further on we are told that the same metal mav 

 occur in a bright metallic or dull pulverulent form. 

 Again, whilst cautiously stating that every definite 

 chemical compound always contains the same elements 

 in the proportion by weight, he says nothing about 

 indefinite compounds, and adds rather recklesslv that 

 "with this constancy of composition goes a similar 

 constancy in all of the properties which characterise 

 the compound." 



When the author has safely extricated himself from 

 the rocks and shoals of his introductory chapters, he 

 gets into smooth water, and the remainder of the 

 book is plain sailing. We presume that "the first 

 year's course " mentioned in the preface has refer- 

 ence to the college student; for it is certainly not 

 a book for a beginner. The absence of all diagrams 

 and experimental details and the use of technical 

 terms without explanation would soon lead him into 

 a labyrinth of difficulties. 



NO. 2163, VOL. 86] 



J. B. C. 



Britiiii icDi.-, (uui iiiif 

 V]). xi -t- 45<S. (Lond' 

 1.1(1. ; New Vorl: • ' 

 V\'u> -s. (nl. lie- 



'liiK auiiiur of tlu-v , .',ell known as an 



enthusiast in the study and cultivation of British 

 ferns, has succeeded in uroducing a work very useful 

 11) all lern-lovers. Hii; 'aas been a matter of 



great dilliculty tor air cover what name has 



been applie-d lo ;. .ny British fern, 



unless he has liad . .mdard collection 



for comparison. 'Ihi- diincuiiy will now be greatly 

 reduced by reference lo the illusfration-; in this book, 

 which consist of 40 mature prints. 



and 319 others. 



Th . are aevoieii to general con- 



sidei • life-history of ferns, culture 



(inducing n\ ni iiusai ion), types of variation, and fern 

 fot s. The attempt to write these introductory chapters 

 in popular language has, as is usual in such cases, 

 resulted in some words being used in a sense differing 

 from that in wl'ieii ili.-v are applied in scientific works. 

 For instance, the oosphere is referred to as 



"the incipient :, and the antherozoids are stated 

 to be iruly vegetative"; and on p. 27 the young 

 plants are hy preference termed "seedlings." 



The remainder of the book contains detailed accounts 

 of the British species, with short notes on their varie- 

 ties and forms. The nomenclature usually adopted in 

 British books has been retained on the ground that 

 this work is intended "rather for the practical ama- 

 teur than for the scientific botanist"; it is to be re- 

 gretted, however, that synonyms are almost entirely 

 omitted, even in the case of such a familiar one as 

 Nephrodiiim filix-mas. The mixture of Latin and 

 English names printed in the same type leaves one in 

 doubt as to whether the final word forms part of the 

 plant-name or is that of its describer or raiser, e.g. 

 " Pteris aquilina crispa cristata Druery" (p. 221); in 

 the case of Polystichtivi piilcherrimiim (p. 211), these 

 names are said to refer to the finder. 



The wonderful variation in our native ferns is strik- 

 ingly brought out in this book, which should stimulate 

 many to become students of this very interesting group 

 of plants, and to assist in solving the problems con- 

 nected with variation. C. H. W. 



Motor Car HiU-Climbing Cliart. To Show the Speed 

 at which a <^ivcn Motor Car can CJitnb any given 

 Hill — to Sliow also tlie Gear upon zchich it can do 

 so — and the Engine Speed in Revolutions per 

 Minute. (London : Edward Stanford, n.d.) Price 

 15. 6d. net. 

 The "Motor Car Hill-Climbing Chart" consists of 

 a card 5^ by fvi inches, on the face of which there is 

 a sliding card. The sliding card has a square hole 

 in it covered by a transparent sheet. On this is draw n 

 a brown curve representing the resistance due t'^ 

 average road and wind resistances at different speeds. 

 Through the window three other curves, the forms 

 of which 1 ' II determined by experiment, may be 



seen. Tl >f different colours, and are adapted 



to suit one e.ii n of the three gears. The sliding card 

 can bt^ set by means of a scale to a position corre- 

 sponding to anv gradient up or down. Then the 

 intersection of the brown curve with one or other of 

 the other curves sliows which gear should be used, 

 what speed the car should go, and the r.p.m. of the 

 engine when the car is in good order. If the cun'es 

 have been produced bv experiment with the particular 

 car, no doubt useful results will be obtained, and that 

 most convenientlv. but until all cars are alike it is 

 difilcult to see what use it will he on somebodv else's 

 car. 



