February, 1910. 



KNOWLEDGE. 



79 



HAD CETACEANS A TWOFOLD ORIGIN ?— It has 

 been repeatedly suggested that the toothed whales are not very 

 nearly related to the baleen whales, and Professor Kiikenthal, 

 in particular, has argued in support of a " diphyletic origin." 

 Dr. Stefan Sterling, a worUer in Kiikenthal's Institute, has 

 recently gone carefully into the musculature of the fore-limb, 

 and finds that in respect to this the toothed whales and baleen 

 whales are not very closely related. Their resemblance is 



one of convergence ; that is to say, the flippers are independent 

 adaptations to similar conditions. The toothed whales diverge 

 further from the typical Mammal and must have had an 

 earlier origin than the baleen whales. Thus anatomy 

 illumines evolution. It is interesting to note that the flipper 

 type of limb nuist have been evolved several times independ- 

 ently, — in Ichthyosaurs, in post-Triassic Plesiosaurs, in 

 Cetacea (twice ?), in Sirenia, and in Pinnipedia. 



RE\'IE\VS. 



AERONAUTICS. 



Tlu- Problem of Fliglit. — B>' Herbert Chatley. B.Sc. 

 IJl pages. 60 illustrations. 9-in. X 6-in. 



(Charles Griffin & Co. Price 10 5 net. I 



This book, which bears the somewhat ambitious title of a 

 " Textbook of .Aerial Engineering," is not one which it is easy 

 to review. The first edition was written some months before 

 Farman, in January, 1908, succeeded in making the first 

 circular kilometre flight in Europe. Owing to the author's 

 absence in China, the present edition is admittedly not up to 

 date, although numerous alterations and additions ha\e been 

 made to the text, and some of the original rather crude 

 illustrations have now been replaced by more accurate photo- 

 graphic reproductions of various aeroplanes. 



There is, however, no mention of the well-known Farman or 

 Bleriot machines, nor does the victorious Gnome engine recei\e 

 any mention, and none of the recent work of the English 

 constructors is described. 



On the other hand this edition is not much blemished b\- 

 misprints, though there are a few minor errois, such as on 

 page 48b " Driwiski " for " Drzewiecki," and " V'oison " for 

 " Voisin." 



Chapter I. deals with general considerations; Chapter II. 

 with essential principles. In Chapter III. when discussing 

 propellers, the author states (in effect) that the total projected 

 blade area should approach very nearly to the disc area, 

 provided the blades are not sufficiently near to cause inter- 

 ference ; this does not seem to be very conclusive. 



In Chapter IV. three methods of starting aeroplanes are 

 gi\en. but no reference is made to the Wright Bros.' pylon 

 and falling weight device. 



Chapter V. on '" Ornithopters," is good, but does not 

 command much interest at the present time ; the author 

 seems to have a particular penchant for the Helicopter, and 

 devotes a good deal of space to this type throughout the book. 



In Chapter VII. on "Form and Fittings of .'Verial Vessels," 

 the author states that "corrugated aluminium for helices and 

 aeroplanes has been foimd to be very efficient," though it has 

 not been used by any successful machine at the present date. 



Some of the appendices are interesting, and are perhaps the 

 most valuable portion of this book. In appendix H. the 

 author discusses landing problems, but apparently has some 

 idea that the aeroplane always meets the ground at its gliding 

 angle ; the operation of the " vol plane " docs not seem known 

 to him. 



The bibliography at the end is not at all complete, nor is 

 the list of aeronautical societies and clubs up to date. On the 

 whole, however, the book gives plenty of food for thought, but 

 the author endeavours to co\er too much groimd, and has a 

 fatal tendency to indulge in mathematical jerry-building ; 

 edifices of most elaborate formulae are piled up on (in many 

 cases) extremely slender foundations, and, as a result, are 

 naturally neither of a permanent nor useful character. 



There is no doubt that Mr. Chatley is an able mathe- 

 matician, and if he will only alloy his theories with a greater 

 number of practical facts, he may then succeed in producing 

 something of value to the aeronautical engineer. 



CHEMISTRY. 



Spark Spectra of flic Mcfals.— By C. E. Gl.SSiNG, F.R.G.S. 

 21 +vii. pages. 10 plates. lU-in. X Sj-in. 



(London: Bailliere. Price 7/6 net.) 



The method of spectrum analysis is now so widely used to 

 ascertain the composition of unknown bodies that this book of 

 Admiral Gissing, which embodies an enormous amount of 

 work, should be welcomed in many directions. It gives a brief 

 description of the prism spectroscope and of the methods of 

 obtaining spark spectra and recording them by photography, 

 but its chief value will be as a work of reference. For since 

 it gives photographic enlargements of the spectra of fifty 

 different metals, alloys and gases, it will be a simple matter to 

 ascertain, by comparison of the spectra and measurement of 

 the wave lengths of the lines, the constituents of any mineral 

 or mineral ore under examination. The photographs are 

 excellently reproduced and notes are given to call attention to 

 the most characteristic lines in each case. 



Ciiiiilirulgc County Gcoiirapliics — Fifcsliirc. — By E. S. 



Valentine, M.A. 187 pages. 64 illustrations. 4 Maps. 



73-in. X5.i-in. 



(Cambridge University Press. Price 1 6 net. I 



The Scottish series of Cambridge County Geographies, so 

 admirably begun with the volume on Lanarkshire, is well 

 continued in the little book under review. By virtue of its 

 position, the ancient kingdom of Fife — a peninsula jutting into 

 the North Sea between the Firths of Tay and Forth, and 

 separated from the rest of Scotland by the Ochil Hills, lends 

 itself specially to treatment as a geographical unit. The 

 uniciue geological phenomena found along its shores, its 

 ancient history, its abundant mineral resources, and last, but 

 not least, its claim to possess the Mecca of golfers, give Fife- 

 shire special prominence amongst Scottish counties. Whilst 

 largely an agricultural county, weaving, fishing, and mining 

 particularly, employ a large proportion of its inhabitants. 

 Dunfermline is the chief seat of table-linen manufacture in 

 the world, and Kirkcaldy is almost equally famous for 

 floorcloth and linoleum. Coal-mining has so progressed of 

 late years that Fifeshire, from the third in 1899, had sprung to 

 the first place among Scottish counties in 1906, in the quantity 

 of coal shipped from its ports. In style, get-np and readability 

 this book upholds the high character of this series : and Mr. 

 \'alentine has worthily maintained the standard set up by the 

 initial volume on Lanarkshire. 



An Elementary Treatise on Co-ordinate Geometry of 



Three Dimoisions. — By R. J. T. Bell. 355 pages. 



9-in. X 6-in. 



(Macuiillan & Co. Price 10 - net.) 



The author is Lecturer in Mathematics at Glasgow University, 

 and has embodied in this book the course of his lectures in 

 solid geometry. .After preliminary matter the book deals 

 chiefly with the Conicoids, but contains also chapters on 

 Ruled Surfaces, Curvature, and Geodesies. It has copious 



