6o4 



NATURE 



[April 28, 1892 



met with in this country in attempts to rear even present- 

 able " specimens " of such favourites in our smoke- 

 beladen and crowded cities and suburbs. 



Then, again, the English reader gathers some informa- 

 tion as to the Western popular names of trees, well known 

 to him by very different ones ; how many English people 

 know what are the "cucumber-tree," the "yulan," the 

 " buckeye," the " butter-nut," and the " button wood " ? 



Bits of history also occur, and incidental notes on the 

 rates of growth of various trees, their ages, &c. So that, 

 after all, there are some dry facts in this singularly quaint 

 and simply written talk about trees. We must not claim 

 much for the work in this respect, however ; and perhaps 

 the chief reason we like the writing is because of its con- 

 trast to the empty and inflated style of too many of our 

 native newspaper articles on similar subjects. 



OUR BOOK SHELF. 



Synopsis of Non-Metallic Chemistry. By William Briggs, 

 B.A., F.C.S. Pp. 90. (London: W. B. Clive and 

 Co.) 



This book is intended for students preparing for the 

 Matriculation Examination of London University. After 

 the contents of an ordinary text-book have been studied, 

 the reader is here supposed to find the more important 

 points which have to be remembered, and which serve 

 to recall the less important. Interleaved note-paper 

 is provided, whereon facts readily forgotten may be 

 recorded. 



As is usually the case with such cram-books, little can 

 be said in favour of the quality of the information 

 supplied. 



Formulae are stated to be "arrangements of letters 

 representing a molecule of a compound," and this defini- 

 tion is illustrated by regarding Fe304 as denoting a 

 molecule. The vapour-density of hydrofluoric acid is 

 given as lo, and the solubility of hydrogen in water as 

 " practically the same at all temperatures from i° to 20' " : 

 neither statement is up to date. Such antiquated terms 

 as basyloiis and chlorous, which are freely employed, 

 might well be replaced ; and to speak of distilling potas- 

 sium perchlorate with strong sulphuric acid is inaccurate. 

 The account given of fractional distillation is worthy of 

 reproduction. The mixture of liquids is heated " up to 

 the lowest of the boiling-points of the liquids present. 

 The whole of that liquid (?) will be converted into vapour, 

 and can be condensed in the usual way. On heating the 

 remaining liquid up to the next boiling-point, we can 

 separate another of the constituents, and so on until they 

 are all separated out. The different liquids thus obtained 

 must be redistilled to get them quite free from the others, 

 small quantities of which may have been distilled over in 

 the first process." 



This last extract is typical of the bulk of the knowledge 

 contained in the book, which, to say the least, savours 

 more of the class-room than the laboratory. > 



A table of contents, a glossary, and three appendixes 

 are provided. The last are concerned with the prepara- 

 tion and purification of substances and with the simpler 

 chemical calculations. A list, with answers, of numerical 

 examples set at the matriculation examinations is in- 

 cluded. 



Chemical Calculations. By R. Lloyd Whiteley, F.LC. 



With a Preface by Prof. F. Clowes, D.Sc, F.LC. 



(London: Longmans, Green, and Co., 1892.) 

 This is still another addition to the numerous manuals 

 on chemical arithmetic, and the points wherein it differs 

 from its predecessors are somewhat difficult to discover. | 



NO. 1 1 74, VOL.45] 



Once more we have specific gravity observations in 

 which corrections for temperature and air displacement 

 are ignored ; and although the author attempts to set 

 right the prevalent misconception as to the meaning of 

 density and specific gravity, it is questionable if he suc- 

 ceeds. According to him, specific gravity is always 

 relative ; it is the same magnitude as relative density. 

 The use of absolute specific gravity — or, shortly, specific 

 gravity with no temperatures of comparison attached — as 

 denoting the weight of unit volume, is here overlooked. 

 From a physical point of view, the definition of the 

 absolute density of a gas as the mass of 11 •16 litres is 

 a needless complication. In ascertaining the percentage 

 composition of a compound it is insisted that, first of all, 

 the molecular weight must be calculated. The examples 

 given to illustrate the rule include apatite, apophyllite, 

 basic lead chromate, &c. The student is thus led to 

 infer, here as elsewhere in the book, that the molecular 

 weights of such bodies can be fixed. 



The freezing-point and boiling-point methods of ob- 

 taining molecular weights are disposed of in two pages. 

 No hint is given that the solutions must be dilute and 

 non-electrolytic, if consistent results are to be obtained ; 

 or that, in general, the interpretation of the results of 

 these methods is still subject to difference of opinion. 



It is erroneous to state that "the alteration in the 

 volume of a gas is proportional to the so-called absolute 

 temperature," or to speak of " Dalton and Henry's lavv.'^ 

 Henry's law is distinct from Dalton's, and is the older by 

 two years. 



We have dwelt on some of the points which seem to 

 call for criticism. On the other hand, the book has its 

 good features. The problems are numerous, carefully 

 selected, and well arranged^ Contents, answers, and 

 index are supplied. It seems to us, however, that,^ 

 instead of being as good as several of its kind already 

 in existence, it, as a new book, should have been better. 



The Year-book of Science. Edited for 1891 by Prof. T. 

 G. Bonney, D.Sc, LL.D., F.R.S. (London : Cassell 

 and Co., 1892.) 



All who have any sympathy with scientific pursuits will 

 heartily welcome the appearance of this epitome of the 

 more important results of the investigations which were 

 published during the past year. Scientific inquiry now 

 covers so much ground that all men of science must be 

 more or less specialists, and it is difficult for them ta 

 keep in touch with the developments in other branches 

 through the usual channels, although it frequently 

 happens that an advance in one subject may throw light 

 upon and induce investigations in another. There are 

 also many engaged in practical pursuits who require a 

 convenient means of determining how far contemporary 

 researches may be technically applied. 



With a well selected staff of contributors, the editor has 

 attempted to meet the wants of all by the present volume, 

 which is divested as far as possible of technicalities. The 

 scope of the work is sufficiently defined by the following 

 paragraph from the editorial : — 



" It is almost needless to remark that this volume is 

 not intended to be a record or catalogue of papers. The 

 endeavour of its projectors and compilers has been to 

 select those memoirs, in each several department, which 

 appeared to be of somewhat exceptional interest, either 

 by throwing light on special difficulties or by being 

 suggestive of further advances." 



In a work of this kind strict impartiality is essential,^ 

 and we see no reason to suppose that the various con- 

 tributors have abused the power vested in them. On the 

 whole, the production is very satisfactory, and "the im- 

 provements which the editor contemplates for the next 

 volume will make it more so. One can only wonder that 

 science has had to wait so long for a year-book of its 

 own. 



