November 23, 1893] 



NA TURE 



75 



detract from the scientific aspect of the vohmie ; such as 

 the statement of the views of the " very intelligent 

 student" on the subject of the eyes of the shrimp 

 (p. 225); the suggestion that the "Sea-devil" of 

 the Mediterranean might well be the "great fish" 

 referred to in the Book of Jonah (p. 222) ; the 

 criticism on Spence Bate's description of Para- 

 thanas zmmaturus, apparently only given to afford 

 the opportunity of quoting an ungallant saying about 

 women (p. 233), and several such like ; or we could have 

 been spared three pages about Birgos latro, or the half- 

 page of aJListification for giving Hansen's most excellent 

 synoptic table of the Cymothoid group. Indeed, the 

 author's desire not to make this manual a " dry and repul- 

 sive catalogue ' has made him write a number of sen- 

 tences which the seriously-minded reader will find it 

 better to pass over with a very cursory eye. To con- 

 clude all we have to say on this aspect of the volume, we 

 have strong objections to urge to the page headings, as 

 being an attempt not to help but to confuse. Possibly the 

 author may not be accountable for these ; they have often 

 so little to do with the subject of the matter in the pages, 

 that it is not unlikely that they were selected by some 

 one as ignorant of the subject as of good taste ; as 

 examples we quote the following : " The tail unique," " A 

 box of branchiae,'"' " An affectionate squeeze," " Perils of 

 baby-farming," " Looking like a buffoon," " How genera 

 are generated," and many such like. 



With all these little defects, which might so easily have 

 been avoided, this volume will be indispensable to the 

 student of this class of Arthropods ; it brings together in 

 an intelligible form an immense mass of literature. In 

 some of the orders most complete lists of genera and 

 species are given, notably among the Isopods. Those 

 species interesting either for their morphological, geo- 

 graphical, or baihymetrical distribution, are invariably 

 mentioned, and so far as we can judge, all the British 

 species are named. Most useful will this volume, com- 

 pact in size and well-packed with information, be to col- 

 lectors. There is at present no one work that can com- 

 pete with it. Perhaps the day may come when our 

 great National Museum may publish a revised list of all 

 known Crustacea, as they have done of the fishes, rep- 

 tiles, and birds ; till then Mr. Stebbing's volume will not 

 lose its value, a value that would be greatly increased 

 should a companion volume be published giving the 

 history of the remainder of this interesting group. The 

 work is embellished by nineteen plates and thirty-two 

 illustrations in the text. 



OUR BOOK SHELF. 



An Elcinoitary Treatise on the Geometry of Conies. By 

 A. Mukhopadhyay. (London: Macmillan, 1893.) 



This work is well adapted for junior students. It 

 treats of the principal properties of the curves, and may 

 well be read after a pupil has mastered his six books of 

 Euclid. The starting point is from the focus and direc- 

 trix definition, and no modern methods (as projections) 

 are employed, nor are the curves shown to be obtainable 

 from plane sections of the cone. Each curve has a 

 chapter allotted to its discussion, which is conducted, as 

 far as possible, on uniform lines. To the parabola are 



NO. 1255, VOL. 49] 



assigned twenty-five propositions, to the ellipse thirty- 

 five propositions, and to the hyperbola thirty-seven pro- 

 positions, with an additional five for the rectangular 

 form. The order of treatment is mechanical descrip- 

 tion, chord properties, and then tangent properties. The 

 proofs should be readily mastered by a boy who knows 

 his Euclid, for they are clearly and simply put, and the 

 author does not assume the truth of a converse pro- 

 position, as we have noticed some writers do. Mr. 

 Mukhopadhyay has read far and wide in his subject, and 

 ha5 brought together in his 800 exercises a large collec- 

 tion of the most interesting problems. Many of these 

 he accompanies with full solutions, and to very many 

 more he furnishes suggestive hints. The figures are 

 white on a black ground. The book appears to be very 

 correctly printed ; at any rate, we have detected very few 

 (easily corrected) misprints. The book appeals success- 

 fully to a larger public than the students of the Indian 

 colleges. 



The Geometrical Properties of the Sphere. (Univ. Corr. 

 Coll. Tutorial Series.) By William Briggs and T. W. 

 Edmondson. (London : W. B. Clive, 1893.) 



In these fifty pages the authors have brought together 

 most of the chief geometrical properties of the sphere, in- 

 tending the book to be used as a companion to their larger 

 one, on mensuration of the simpler figures, by students 

 preparing for the intermediate examinations in Arts and 

 in Science of the University of London. The three 

 chapters into which the subject is divided lead the reader 

 from the elementary definitions relating to great and 

 small circles, poles, lunes, Sec, through the numerous geo- 

 metrical properties of spherical triangles and their anti- 

 podal triangles, polar triangles, supplemental triangles, 

 and finally to the determination of the area of lunes, 

 spherical triangles, spherical polygons, and the spherical 

 excess. The definitions and theorems are expressed 

 quite clearly throughout, while the figures leave nothing 

 to be desired. As an introduction to works on spherical 

 trigonometry, students will find this book a most helpful 

 guide. Two minor slips in construction will be found : 

 one on page 6, line 6, where for CT read TC ; and the 

 other on page 18, line 9, where for oa and od read ao 

 and bo. 



A Key to Carroll's Geometry. By J. Carroll. (London: 



Burns and Gates, Ltd., 1893.) 

 This key contains the solutions of the exercises in 

 orthographic projection and solid geometry, which are 

 given in the author's book on geometry. The solu- 

 tions seem to have been thoroughly and carefully 

 worked out. The figures are generally drawn to full 

 scale, but sometimes half-scale has been employed. 

 Lines of projection are clearly indicated — an important 

 factor in some of the more complicated figures. The 

 key should prove a help to beginners, who should study 

 well the questions and their accompanying figures. 



LETTERS TO THE EDITOR. 



\_The Editor does not hold himsef responsible for opinions ex- 

 pressed by his correspondents. Neither can he undertake 

 to return, or to correspond with the writers of, rejected 

 manuscripts intended for this or any other part (7/N.\TURE. 

 No notice is taken of anonymous communications. \ 



"Geology in Nubibus." — A Reply to Dr. Wallace and 

 Mr. LaTouche. 



Dr. Wallace has taught us a great deal, and among those 

 lessons is <he supreme virtue in scientific controversy of courage 

 and candour. lie must forgive me therefore for answering 

 promptly, and I hope frankly, his last letter in Nature. In 

 this letter he appeals from your columns to a non-scientific 



