March 20, 1879] 



NATURE 



457 



carried out, the results of which, owing to Dr. Sachs's un- 

 timely decease, will, we fear, never be given to the public. 

 Leaving Calabozo, Dr. Sachs continued southwards to 

 San Fernando de Apure, and thence down the Apure and 

 Orinoco to Ciudad Bolivar, the capital of this part of 

 Venezuela. From Ciudad Bolivar steam quickly carried 

 him to Trinidad, and thence back to Europe. Of this 

 section of his journey, as of the former part, Dr. Sachs's 

 narrative is full of interest — nor will any one who reads it 

 fail to regret that so promising a life should have come to 

 such an early conclusion. 



OUR BOOK SHELF 



Education as a Science. By Alexander Bain, LL.D. (C. 

 Kegan Paul and Co., 1879.) 



This work, belonging as it does, to The International 

 Scientific Series, naturally calls for some notice in our 

 columns. We must confine our remarks, however, to 

 the portions which deal with Mathematical, Physical, or 

 Natural Science. The author, though Professor of 

 Logic and English Literature, has already appeared 

 before the pubUc as one of the Editors of Arnotfs 

 Physics, and has laid down the law in a somewhat 

 peremptory way about Elementary Geometry. We 

 expect to find, therefore, accurate science, and above 

 all, clear and definite composition, in his work. 



The first of the following extracts supphed a hint 

 which enables us to make the book review itself. We 

 have taken the liberty of itaUcising a few words, in other 

 respects we quote verbatim. 



" Definite descriptions of definite failures, without note 

 "or comment, are a power to punish. WTien there 

 "are aggravations, such as downright carelessness, a 

 " damaging commentary may be added ; but in using 

 "terms of reprobation, still more strict regard has to 

 " be paid to discrimination and justice. The degrees of 

 "badness are sometimes numerical .... this very 

 "definiteness literally stated is more cutting than 

 "epithets." 



" The phrase 'caeteris paribus' (other things remaining 

 " the same) is a mathematical coinage, for guarding 

 "against the error of supposing that a course \sic) will 

 "produce its effect under all circumstances indiscrimi- 

 "nately." 



"The ad\'antages above set forth are such as Mathe- 

 ** matics is peculiarly fitted to give, and without which 

 " they are scarcely ever attained at all. In so far as the 

 " physical sciences unfold similar advantages the way is 

 " paved for them by Mathematics. To this short sketch 

 " of what Mathematics does, we should, for the sake of 

 " clearness, append what it does not do, and must be left 

 " undone, if we stop with it." 



" The earlier parts of such subjects as Geometry and 

 " Algebra need the longest iteration : the progress should 

 "be at an accelerating rate. The higher Mathematics 

 " should not be commenced w^ith immature or incapable 

 " minds.'"' 



" How to embody the actual problems in matheniatical 

 "language, — for example, the problems of motion in the 

 " scheme of differential coefficients, — is a standing em- 

 *| barrassment, not to be met by any of the arts of 

 " ordinary tuition." 



" Try a child tolift a heavy weight first by the direct 

 "pull, . . . ." 



" Many trials must be allowed to get a child into a new 

 "shade of vowel, as, for example, when Scotch {sic) 

 " children have to learn the English sound of 'all.' " 



" A high wrangler is a man professionally fitted for some 

 " special post involving Mathematics ; but, if he turns to 

 "one of the other professions — Law, Medicine, the 



" Church, the Public Service, he has incurred an irreme- 

 " diable waste of human strength." 



Having attentively perused these extracts, the reader 

 will probably be prepared to consider the following state- 

 ment as more than plausible : — 



"A purely psychological or metaphysical education 

 " might be the worst case of any . , . ." P. G. T. 



Ufe in Asiatic Turkey. A Journal of Travel in Ciliciaf 

 Isauria, and parts of Lycaonia and Cappadocia. By 

 the Rev. E. J. Davis, M.A. Map and Illustrations. 

 (London : Stanford, 1879.) : 



Mr. Davis resides as Chaplain at Alexandria, and the 

 present thick volume is the result of a tour in Northern 

 SjTia, in the smnmer of 1875. It is surprising that a 

 region so full of interest should have been so little visited, 

 and therefore Mr. Da\ns's account of what he saw is 

 specially welcome. That there is much to interest in 

 these parts is evident from aU that Mr. Davis teUs us, 

 and his quiet and painstaking narrative will well reward 

 a careful perusaL The pictures, coloured, from drawings 

 by Mr. Davis, are unusually good, and add greatly to the 

 interest of the volume, which is likely to take its place as 

 a standard reference- work on the region with which it 

 deals. 



LETTERS TO THE EDITOR 



[ TTu Editor does not hold himsdf responsible for opinions expressed 

 by his correspondents. Neither can he undertake to return, or 

 to correspond vnth the writers of, rejected manuscripts. N0 

 notice is taken of anonymous communications. 



\The Editor urgently requests correspondents to keep their letters ms 

 short as possible. Ihe pressure on his space is so great that it 

 is impossible otherwise to ensure the appairance even of com- 

 munications containing interesting and novd facts,} 



Tempel's Comet 



We find in Nature, vol. xix. p. 347, some detailed particohrs 

 about the return of the comet 1867 II. (Tempel) in the course of 

 the present year. In this article Sandberg's calculations are also 

 taken into account. The real value of his studies about this 

 comet seems to be but little known, as in other instances as well, 

 new calculations are based upon diem. In the Astron. Nach. 

 Sandbei^ has only given a very short account of the results of 

 his researches, and it is therefore but natural that their r al 

 value must be more or less concealed. Sandberg has published 

 the details of the first determination of the orbit in a special 

 treatise (Specimen Inaugurale de Orbita Cometx II., 1867, 

 Zwollae, 1869), which seems to be not very much k-uown, and it 

 is not necessary to read much of this work to make sure of the 

 negative value of the calculations. - 



I now take the Uberty to give here some short nodces, which 

 are, however, quite proof enough to keep astronomers eventually 

 from unnecessary calculations. Sandberg makes use of all 

 observations, and forms the normal places by the deviations of 

 the different observations from the provisional ephemeris. In 

 doing this he rejects, "prompted by the example of others," 

 {sic) all observations which deviate more than i'5s. in R.A., and 

 20" in D. from the ephemeris, and not firom the average. If, for 

 instance, as with a normal place the mean deviation comes to 

 -|- 14" in D., he rejects observations which deviate 6" from this 

 average, whereas he accepts others to their full value, the 

 de\'iation of which from the average is nearly 30" ( - 14" from 

 the ephemeris). 



According to this proceeding is the accuracy of his calcula- 

 tions. An observation .of Pulkowa deviates, according to his 

 calcidation, firom the normal difference in D. ( - 2"'2} 21" (iS' '9). 

 If he had token the parallax with correct sign, the observation 

 would deviate 4" from the average. In the same manner the 

 above-mentioned great deviation from the average is wrong, and 

 does in reality only come to about 3". These facts are sufi&cient. 

 It would be easy to mention many others of similar natiure, but I 

 do not think it necessary to take up more room in your esteemed 

 periodical. 



W. Valentiner 



Mannheim Observatory, March 10 



