50 



NA TURE 



[December 14, 1899 



where the symbol Fj is used, in a single formula, to de- 

 note both the position of a point on the diagram, and 

 the distance of that point from another point A. With 

 a few such exceptions, however. Prof Suter's book 

 handsomely fulfils the purpose for which it was written. 



The aim of Mr. Percival has been to supply the 

 reader, within reasonable compass, with such a knowledge 

 of optics as would be of use to an ophthalmic surgeon. 

 The author further expresses a hope that mathematical 

 students may find it useful as an introduction to more 

 advanced works on geometrical optics. The subject is 

 treated throughout, from a mathematical point of view, 

 in a manner that leaves little to be desired. An ophthalmic 

 surgeon might possibly prefer to have the subject pre- 

 sented less from the mathematical, and more from the 

 physical point of view ; whilst a student of physics would 

 probably wish to see greater prominence given to 

 experimental methods. ^ Lord Rayleigh's investiga- 

 tion on the advantage of stopping out the middle of a 

 lens, in preference to its peripheral region, is not 

 mentioned. Further, the name of Helmholtz is not men- 

 tioned in connection with the ophthalmoscope. But the 

 most serious blemish is the total absence of an index ; this 

 absence is particularly damaging to a book which, from 

 its nature, should serve as a work of reference. The 

 type and general structure of the book are otherwise 

 admirable. A few sentences, such as the following, 

 could be improved : — 



" The first principal focus (Fj) is the point on the 

 principal axis where the incident rays intersect, or would 

 mtersect if produced, which emerge from the system 

 parallel to the axis " (p. 253, lines 6-9). 



" The two nodal points are mutually the image of each 

 other" (p. 253, lines 30-31). E. E. 



A Practical hiltoduction to the Study of Botany ; 

 Flowering Plants. By Prof J. Bretland Farmer, 

 M.A. (London : Longmans, Green and Co., 1899.) 

 Prof. Farmer's work is that of an expert dealing with 

 a science with the details of which he is thoroughly 

 familiar, both as a student and as a teacher. Its pages 

 show the firm grasp that enables him to make clear even 

 abstruse parts of the science, and that gives confidence 

 to those who use the book with the care and close atten- 

 tion that it deserves. The plants employed as examples 

 are excellently selected, and the necessity of verifying 

 each point described upon the plant itself is constantly 

 enforced. The discipline and information gained by 

 any one that works honestly through the course of study 

 here planned out will be found most valuable as a sure 

 base on which to build up a thorough knowledge of 

 botany. The woodcuts are good, but might have been 

 more numerous with advantage to those that use the 

 book without the aid of a teacher. In the absence of 

 figures a beginner may, if unaided, find it difficult to 

 obtain some of the plants named, though the selection 

 has been very largely made from species that ought to 

 be known to most people of ordinary education. The 

 use of technical terms is restricted within due limits, 

 and their meanings can be gathered from the examina- 

 tion of the specimens in connection with which each is 

 first employed. The procedure to be followed in the 

 examination of the specimens and in the experiments in 

 physiology is simply and clearly explained, though here 

 and there one meets with evidences of haste or pressure. 



Primeval Scenes; being some Comic Aspects of Life in 



Prehistoric Times. By Rev. H. N. Hutchinson, B.A. 



Illustrated by J. Hassall and F. V. Burridge. 



(London : Lamley and Co., 1899.) 



The drawings in this volume are similar in character to 



the amusing " Prehistoric Peeps " contributed to Punch 



by Mr. E. T. Reed a few years ago. In preparing his 



drawings, Mr. Reed worked to produce striking effects ; 



NC. 1572, VOL. 61] 



and as there is artistic as well as poetic licence, he was 

 justified in introducing into his pictures any objects- 

 which would appeal to the sense of the ludicrous. But to 

 the mind of the pah\;ontologist, a picture containing pre- 

 historic humans in company with such old forms of life 

 as Pterodactylus and Stegosaurus, and creatures which 

 had their origin in the artist's imagination, appears a 

 trifle grotesque, though it may afford amusement to 

 thousands of persons who do not understand the incon- 

 gruity of the arrangement of characters depicted. 



In the present volume an attempt is made to combine 

 instruction and amusement by representing creatures in 

 various comical aspects which were possibly all seen by 

 some of our primeval ancestors. In other words, the 

 drawings are in keeping with the discoveries of prehistoric 

 archaeology and the facts of geology. Twenty scenes are 

 depicted, and adjacent to each is a brief description of 

 the chief characteristics. The pictures are, in the opinion 

 of the writer, not to be compared as regards their divert- 

 ing character with Mr. Reed's inimitable sketches, and 

 the descriptions which accompany them are of too 

 general a character to call for criticism. But the scien- 

 tific accuracy of the drawings in so far as they represent 

 animals which are known to have been contemporaries 

 of man is certainly a merit ; and for this reason the 

 book is a suitable present for a boy with scientific predi- 

 lections and a lively imagination. 



A Treatise on Surveying. Compiled by R. E. Middleton, 

 M.Inst.C.E., and O. Chadwick, M.Inst.C.E. Part i. 

 Pp. xiii -h 283. (London : E. and F. N. Spon, Ltd., 

 1899.) 



This work seems to have had its origin partly out of 

 consideration for the needs of surveyors whose home- 

 training is too restricted to qualify them for colonial 

 appointments, where a knowledge of geodetic work is 

 required, and has in addition no less an object than the 

 raising of the standard of qualification for English 

 diplomas in surveying. We are told that the Council of 

 the Surveyors' Institute was approached by the authors 

 and others interested in these matters, and agreed to 

 adopt this text-book if satisfied with it, but we are left in 

 doubt as to whether it has received the approval of that 

 body. 



A general idea of the scope of the present volume may 

 be gathered from the titles of the chapters, namely, 

 " chain surveying ; optics, magnetism, &c. ; description 

 and adjustment of instruments; traverse surveying;, 

 minor triangulation ; the plane-table and methods of 

 using it ; levelling and contouring." Geodetical and 

 astronomical determinations, as well as marine, route, 

 and other special surveys are left for the companion 

 volume, so that the form of publication is well suited to 

 the requirements of the two chief classes of students. 

 We find the explanations of the various instruments, 

 processes, and principles sufficiently full and clear, while 

 sound practical methods of making and entering observa- 

 tions and presenting the final results are given through- 

 out. No particular originality is claimed, but the special 

 merit of the book lies in the great care with which the 

 compilation has been made, and the thoroughly practical 

 spirit which pervades it. It certainly makes a good bid 

 for a place among standard text-books. 

 The X-Ray Case Book., f 01 Noting Apparatus., Methods 



and Results. By David Walsh, M.l). (London: 



Baillifere, Tindall and Cox, 1899.) 

 Forms are provided for recording the electrical and 

 photographic conditions under which Rontgen photo- 

 graphs of medical and surgical cases are obtained, and 

 for the entering of notes on the points brought out by an 

 examination of the photographs, or by visual observ- 

 ations with a fluorescent screen. Full diagrams of the 

 human body are given for convenience in recording 

 observations. 



