Januaky 2, 1899.] 



KNOWLEDGE, 



15 



and also in the Indian Government ofiSces and judicial courts. 

 That work contained tables of all the eclipses of the sun visible 

 in India for a period of one thousand six Imndred 3'ears, and it 

 has now been supplemented by tables of the lun.ar eclipses for 

 the same period (a.d. 300 to 1900) ; the calculations being, as 

 in the chief volume, based upon Von Op])olzer's Cojh'ii dei- 

 Fiiisti'nihse. We heartily welcome this completion of so 

 valuable a work. We regret to notice the death of the Pandit 

 Sankara Balki-ishna Dikshit. who collaborated with Mr. Sewell 

 in the " Calendar,' and who rendered assistance in the present 

 supplement to it. 



,1)1 Intrfiduction to the Scifnre ami Prnctlcc of Qualifal/re 

 Anali/sis. — I'luityanic. By Chapman .Tones, F. I.e., r.c.s. (Mao- 

 millan.) Illustrated, lis. It is fitting tliat Mr. .Tones should 

 incorporate the words " .Science and Practice" in the title of bis 

 book, for it is just this feature of reducing the numberless 

 operations of the analytical chemist to a scientific, as distinct 

 from the mere empyric form, which constitutes the value of the 

 work. Indeed, considering that there are scores of books on 

 qualitative analysis .already in the market, nothing less than a 

 radical innovation of the kind in question would be sufficient to 

 justify the addition of one more to the already long list. We 

 are at one with BIr. Jones where he says that " for teaching the 

 vielliod of work, it is not only unnecessary but undesiriible to 

 attempt to include either all classes of comijounds, or all the 

 reactions of those that are considered." The object of all 

 teachers should be to help the student to acquire a sound 

 method rather than to fill his mind with innumerable isolated 

 reactions, so that, understanding the principles of analysis, 

 instead of enslaving himself to the mystic rule-of-thumb routine, 

 he can easily extend his work to other substances than those set 

 for pr.actice in the laboratory. We have known students quite 

 helpless, after a long course of instruction, to set about tlie in- 

 vestigation of an unknown mineral, where there is but little 

 externally to indicate the nature of its composition. This 

 weakness is due to the fact that the student, in general, acquires 

 his analytical knowledge by operating on bodies of known com- 

 position, which serve as a sort of alphabet for the construction 

 of words — words, which if properly put together, will spell the 

 composition of the body under examination. Now, in the book 

 before us. the author has put forth his utmost powers to con- 

 centrate the light of reason on every experiment, observation 

 and inference ; from innumerable reactions he evolves an 

 orderly system — a system that may be adapted to various cir- 

 cumstances, and the student is encouraged to consider the tables 

 given as guides rather than as rigid rules, when he has had a 

 little experience and can judge for himself. 



The Pariillaxes '</'61' and Gl- Cijgni. By Dr. Herman Davis. 

 (New York, 1898.) This is No. 1.3 of the series of memoirs 

 upon the reduction of the measures of the photogra])hic jilates 

 taken by Dr. Lewis Rutherfurd in the years 1871-1874, and 

 which are now being published by the Observatory of Columbia 

 University, New York. The high value of these photographs 

 is now widely recognized, but several points of especial interest 

 are brought out in Dr. Davis's paper. In the first place it was 

 found that the probable error of an observation in the dis- 

 placement on the arc of a great circle is little greater in measures 

 01 angle than of distance. Secondly, the parallax is ditt'erent 

 for the two components 61' and 61°. 



For 61' it is 

 For 61-' it is 



+ n-360" ± 0-0146". 

 + 0-288" ± 0-031". 



This bears out the opinion of Prof. Burnham that this pair 

 forms only an optical double, and that no true 01 bit can be 

 drawn through their positions. But since the two stars have 

 very nearly the same velocity in space, Prof. Davis advances 

 Wilsiiig's theory, that there may be a third dark body round 

 which 61' Cygni revolves. Incidentally, Prof. Davis brings a 

 very serious indictment against the value of the Oxford 

 parallactic results. " I have examined,'' he says, " the eight 

 sets of normal equations given in the work on 61 Cygni, pages 

 17-63, and among the eight sets have not found one which is 

 correct in every quantity. This criticism applies not only to 

 the normals for (il Cygni, but for many of the other stars 

 as well." 



Weather Lore. Compiled and arranged by Richard Inw.ards. 

 (London ; Elliot Stock.) Illustrated. 7s. 6d. This is the 

 third edition of a work intended to present a complete view of 



weather science from its traditionary and popular aspects. It 

 contains two hundred and four pages of proverbs, curious 

 rhymes, quaint sayings, archaic wise-saws, and out-door rules, 

 and will be of especial interest to the man whose good fortune 

 enables him to live in the country. The volume, in addition to 

 these interesting features, contains the essence of observations 

 made by close observers of the skies, and has an instructive 

 picture of the forms of clouds occurring at difl'erent altitudes. 

 It is only necessary to note the conversations which one over- 

 hears or takes part in during a single day to convince one's self 

 of the widespread nature of these sayings about the weather. 

 Who has not heard " Plenty of berries indicates a severe 

 winter," p. 184, and yet, since the berries, of course, indicate 

 juist conditions and not future ones, it is difficult, unless provi- 

 dential foresight is imported into the case, to account for its 

 origin. There ai'e many sayings with which one is familiar, 

 and which defy any national explanation, but the reader must 

 be referred to Mr. Inward's exh.austive and interesting collection 

 itself in order to discover how trustworthy, and also how con- 

 tradictory, weather predictions preserved in folk-lore can be. 



Remarlahle Eclipxea. By W. T. Lynn, f.r.a.s. (London : 

 Edward Stanford, '26 & 27. Cockspur Street, Charing Cross, S.W.) 

 1898. Third Edition. Revised. The success of Mr. Lynn's 

 convenient and carefully written little handbooks is apparent 

 in the rapidity with which successive editions are called for. 

 The first edition of this summary of the leading facts connected 

 with the chief eclipses of history appeared in 1896, and the 

 third is now before us. A brief notice of the two last total 

 solar eclipses, 1896 and 1898, and of the circumstances of the 

 two approaching ones are included in it. 



Introduction to Algebra. By G. Chrystal, M.A . ll.d. (Adam & 

 Chas. Black.) 5s. According to the author of the book before us 

 the old methods of teaching algebra are at fault, and intended rather 

 for the solution of examination problems than for tlie purposes of 

 every-day life. We are convinced that Prof. Chrystal has made a 

 refreshing departure, and although there is a rather forbidding ap- 

 pearance about the treatise, students may take heart, for the new 

 method of treatment of the various theorems of algebraic science we 

 think will gain supremacy over the old systems of teaching algebra. 

 A mathematical truth is net made part of the mental furniture of a 

 pupil by merely fiu-nishing hini with an irrefragable demonstration ; 

 he must see not only where it succeeds, but where it fails to apply, 

 and tliis book will contribute towards that end. 



Practical Mechanics. By S, H. Wells. (Methuen & Co.) 

 Illustrated. 3s. 6d. The Battersea Polytechnic, up to a recent date, 

 was almost the only institute in London which contained a mechanical 

 laboratory, furnished with the apparatus tor verifying all the principal 

 laws of mechanics by the students themselves. We therefore welcome 

 a text-book based on the course of study pursued in that laboratory, 

 and cannot but think such a book will be a substantial aid to the 

 principals of other institutes in combining a course of practical 

 mechanics with the ordinary lectures. The text is written in an in- 

 telligible style, and is illustrated in a suitable manner by photographs 

 of the actual apparatus used at the Battersea Polytechnic. With the 

 help of this book a teacher may convey information which the 

 student can assimilate without that verbose waste of energy which 

 charai'terises the work of many preceptors. 



Social and Political Hconomi/. Essays and Letters by Thos. 

 Judge. Edited by his son, T. Geo. Judge. (London : Simpkin, 

 Marshall .t Co.) 33. 6d. We cannot discover any adequate reason 

 for the publication of these essays and letters, which are as discursive 

 as they are inconclusive, and we fear must disappoint the modest 

 hope of their editor, that they " may introduce some light, however 

 small," into the consideration of some interesting and important 

 subjects. 



Handbook for Literary and Debating Societies. By Laurence 

 M. Gibson. (London : Hodder & Stougbton.) 3s. 6d. A useful 

 volume for the purpose in view, containing an outline of the leading 

 arguments on both sides of a large number of subjects, together 

 with a list of references in each subject. 



An Introduction to Practical Phgsics. By D. Rintoid. (Maemillan.) 

 Illustrated. 2s. 6d. Based on the laboratory notes which have been 

 in use at Clifton College for some years, this book is intended for 

 beginners — a book which " will present no ditlicidty to the average 

 boy " of thirteen or fourteen years of age, and " all tlie experiments 

 described are capable of being performed with the most simple and 

 inexpensive apparatus." An inspection of the contents does indeed 

 indicate that tlie author has contrived to extract a maximum amount 

 of practical knowledge out of a minimum outlay in the way of 

 materials, and although there is little evidence of originahty of 



