June 12, 1884] 



NA TURE 



H3 



writer's garden the sparrows are at this moment doing 

 their best to clear the rose-trees of the " green-fly " that 

 infest them, and there can be no doubt that at this season 

 the sparrow is almost entirely insectivorous ; at other 

 seasons it is almost equally granivorous ; possibly a 

 judicious thinning of sparrows may be salutary, but 

 those who advocate wholesale slaughter should bear in 

 mind the results of the indiscriminate destruction of 

 raptorial birds in these islands. 



Miss Ormerod is not always happy in her nomenclature. 

 Excepting in one book there is no such thing known as 

 " Hybemia prosapiaria " (p.' 5), the specific appellation 

 rightly belonging to an entirely different insect ; more- 

 over had she consulted any recent work or list on Micro- 

 Lepidoptera she would not have penned the footnote that 

 appears at p. 67. 



The illustrations (even if most of them be old and 

 familiar) are good, and add to the usefulness of the 

 Report. 



In future Reports we think it deserves Miss Ormerod's 

 consideration whether a meteorological summary in 

 tabular form would not prove a useful addition, compiled 

 especially with regard to the comparative abundance or 

 scarcity of particular injurious species in former years, 

 in connection with the temperature and rainfall in every 

 month of each year. R. McL. 



OUR BOOK SHELF 

 A n Elementary '['realise en /he Integral Calculus, con- 

 taining Applications to Plane Cm ves and : 

 with Numerous Examples. By B. Williamson, F.R.S. 

 (London: Longmans, 1884.) 

 A work by Mr. Williamson is like good wine, and needs 

 no commendation from us. We note that this has reached 

 a fourth edition, but Mr. Williamson does not rest content 

 with what he has already achieved. He has given a 

 touch here, brought out into greater prominence a feature 

 there, and not only so, but he has at last added a new 

 detail in the shape of a chapter on multiple integration. 

 In our notices of former editions we have drawn attention 

 to the absence of such a chapter, and we are glad to see 

 that he has at last introduced what he hopes " will be 

 found a useful addition to the book. - ' We need only re- 

 mark further that this edition has 393 pages against 373 

 pages in the third edition. 



An Elementary Treatise on Solid Geometry. By Charles 



Smith, M.A. (London : Macmillan and Co., 1SS4.) 

 Mr. Smith has already won his spurs as a mathematical 

 writer by his admirable " Conies." This work, as far as 

 possible, is on the same lines. It is not intended to 

 supersede the classic treatises by Salmon and Frost any 

 more than his former book was to take the place of the 

 splendid work on " Conies " by the former of the above- 

 named writers. A feature in Mr. Smith's treatment of 

 the subject is the early discussion of the different surfaces 

 which can be represented by the general equation of the 

 second degree ; and in the way in which these surfaces 

 are here handled we think the student will be much in- 

 terested. The discussion is full and very clear. An 

 excellent collection of exercises adds much to the value of 

 the book for students : those in the body of the chapters 

 being well fitted to bring the text home to the reader. 

 For the majority of students we should say, " Read Smith's 

 ' Solid Geometry,' and you will not need any other work." 

 Those who wish to penetrate into the inmost recesses will 

 find that they have been helped by the study of this work 



to attack the masterpieces referred to at the outset of our 

 notice. 



A Collection of Examples on the Analytic Geometry of 

 Plane Conies j to which are added some Examples on 

 Sphcro-Couies. By R. A. Roberts, M.A. (Dublin 

 University Press Series, 1884.) 

 We had the pleasure of noticing with commendation 

 (Nature, vol. xxvi. p. 197) a previous collection of 

 examples by Mr. Roberts on conies and some of the 

 higher plane curves. This has all the merits of the 

 former work, with, we fancy, increased power and skill in 

 the methods employed. A portion of the exercises is 

 common to both works. Much space is devoted to the 

 discussion of properties of circles connected with a conic, 

 especially of circles having double contact with the curve. 

 Great use is here made, and effectively, of elliptic coor- 

 dinates. "This method simplifies greatly the study of 

 relations involving the angles of intersection of such 

 systems," i.e. as have double contact with two fixed con- 

 focal conies, " whose differential equations take a simple 

 form." In all there are fifteen chapters, the last of which 

 treats of sphero-conics ; in this chapter also much use is 

 made of elliptic coordinates. The collection is likely to 

 be very serviceable to junior students, and will be con- 

 venient for reference generally. After perusal we have 

 not detected, we believe, any errata that will cause such 

 students as can use the book with profit any trouble. 



Mineralogy. Vol. II. Systematic and Descriptive. 



By J. H. Collins, F.G.S. (Collins's Advanced Science 



Series.) (London and Glasgow: W. Collins, Sons, and 



Co., 1SS3.) 

 This little book is not, neither does it profess to be, more 

 than a dictionary of minerals. The names, localities, 

 and general characters are given as briefly as possible ; 

 and the work seems to be brought up to latest date. 



The only point in which the author lays claim to ori- 

 ginality of treatment is the classification, and it is precisely 

 here that exception may be taken to the book, with its 

 system of Pyritoids, Spathoids, Haloids, Plethoids, 

 Brithoids, &c, and partial neglect of isomorphous groups. 

 Cerussite, for example, is grouped with phosgenite instead 

 of with aragonite, witherite, &c. 



There are a number of crystal figures, but the notations, 

 where used, are not consistent ; and in one case, where 

 the cleavages ofbarytes are wrongly described, the notation 

 is meaningless. 



There are several typographical and other errors which 

 should be corrected in a second edition — e.g. " Senaviza " 

 (p. 61) should be "Serravezza" ; feather-ore (p. 60) should be 

 referred to jamesonite, and not to berthierite ; " eulitite " 

 (p. 239) should be " eulytite." 



It can scarcely be expected that the book will be much 

 used by the "practical miners, quarrymen, and field- 

 geologists " for whom it is intended. The other readers 

 for whom the author writes, " students of the science 

 classes," may however find it a useful and compendious 

 book of reference, as containing a very complete list of 

 minerals. 



Handbook of Vertebrate Dissection. Part III. " How to 

 Dissect a Rodent." By H. Newell Martin, D.Sc, M.D., 

 M.A., and William A. Moale, M.D. (New York : Mac- 

 millan and Co., 1884.) 



In the third of their series of Handbooks of Vertebrate 



Dissection, Drs. Martin and Moale describe a mammal, 



taking as a type the common rat. 



In spite of the authors' remark in the preface that "he 



who aspires to become a comparative anatomist, and yet 



finds a rat too small for the observation of all the main 

 i facts in its structure, has mistaken his vocation," we think 



that, for beginners, a larger mammal would have been 

 1 preferable—at any rate for those who do not aspire to 



