Mav 5, 1910] 



NATURE 



275 



with the general mathematical theory of electro- 

 magnetic waves, with special reference to transmis- 

 sion and telephone lines, and in the sixth chapter 

 Hertzian telegraphy is briefly discussed from the 

 practical side. The next two chapters, forming the 

 second part of the volume, deal with harmonic 

 analysis and non-harmonic E.M.F. 's and currents, 

 and bear directly on the problems met with in alter- 

 nating-current machinery. The mathematics is ad- 

 vanced, and the book is only suitable for advanced 

 students. In an appendix are given eight\'-eight 

 problems for the student to work out, and there are 

 a number of very excellent diagrams. 



(2) Prof. Kennelly describes his book as an elemen- 

 tary treatise ; it covers both the theoretical and 

 practical side of wireless telegraphy and telephony, 

 and is admirably suited for the reader with only very 

 slight technical knowledge. The exposition of the 

 theoretical side is clear, and the description of 

 practical methods, though short, is sufficient to give a 

 general idea of the present position of the art. The 

 only objection which we have to raise against the 



j book is on account of the diagrams, which are 

 j numerous but far from clear. Those in the earlier 

 ; part of the book especially are on so small a scale 

 that they are practically unintelligible; this is the 

 ' more to be regretted as the type and paper are excel- 

 i ient, and there is no apparent reason why the dia- 

 j grams should not be equally well reproduced. 



(3) Dr. Erskine-Murray's little book is a popular 

 exposition of the methods and present position of wire- 

 less telephony. Dr. Erskine-Murray combines a 

 thorough knowledge of his subject with the power of 

 clear and simple explanation, and we know of no 

 better book for those of the general public who are 

 anxious to know how wireless telephony now stands. 

 We are rather doubtful whether the somewhat rosy 

 view of the future taken in the last chapter is likely 

 to be realised, although the advances already made 

 make one chary of expressing too strong a doubt. 



(4) No stronger evidence of the assured position of 

 wireless telegraphy as a commercial means of com- 

 munication could be afforded than the publication of 

 this little Government handbook. The book itself does 

 not call for much comment, since it contains only 

 instructions and regulations for operators on board 

 ship or in coast stations, but that such regulations 

 should be called for is a more convincing proof that 

 wireless telegraphy has settled down to the steady en- 

 joyment of its own kingdom than any number of 

 treatises or popular booklets. The position of wire- 

 less telephony to-day is much the same as that of 

 wireless telegraphy ten 3'ears ag^o. Will 1920 see the 

 issue of a Government handbook for wireless telephone 

 operators ? 



nVR BOOK SHELF. 



The Liverpool Geological Society. A Retrospect of 

 Fifty Years' Existence and Work. By W. Hewitt. 

 Pp. 117. (Liverpool: C. Tinling^ and Co., Ltd., 

 1 9 10.) 



The Liverpool Geological Society, which was estab- 

 lished on December 13, 1859, has signalised its 

 jubilee by the publication of this volume, which in- 



NO. 2 1 14, VOL. 83] 



eludes an account of the history of the society and 

 its geological labours, a list of papers printed in the 

 Proceedings, and biographical notices of some past 

 members. The society originated from a meeting 

 held at the residence of G. H. Morton, who was its 

 real founder, and for about forty years the chief mov- 

 ing spirit among the members. A capital portrait of 

 him is given. Well known as the author of a volume 

 " On the Geology of the Country around Liverpool," 

 and of a series of important papers on the stratigraphy 

 and palaeontology- of the Carboniferous rocks of Flint- 

 shire, he was one of the most distinguished of pro- 

 vincial geologists. By regarding the country within 

 fifteen miles of Liverpool as their proper sphere of 

 study, the society took the Carboniferous limestone 

 series of Flintshire as their foundation-rocks, together 

 with the succeeding Millstone Grit, Permian, Trias, 

 Pleistocene, and Recent deposits. 



On all these formations the members of the society 

 have done excellent work. Undoubted Permian strata, 

 including a bed of magnesian limestone with 

 Schizodus, were described by Mr. E. Dickson at 

 Skiliaw Clough, near Parbold. The researches of the 

 late T. Mellard Reade on the Triassic rocks, the 

 Glacial Drifts, and the recent physical changes in the 

 Lancashire district are well known. His portrait is 

 included; also that of Dr. Charles Ricketts, another 

 enthusiastic worker who dealt with many local 

 physical problems. There is one other portrait, that 

 of Joseph Lomas, who had done much in investigating 

 the fauna, flora, and origin of the Trias. Unfortun- 

 ately, a railway accident in Algeria terminated the 

 life of this zealous and genial worker at the early 

 age of forty-eight. Photographic plates are given of 

 the famous footprints of Cheirotherium from the 

 Keuper Sandstone of Storeton, in Cheshire, described 

 by Morton ; and of the gypsum boulder from the 

 Glacial Drift of Great Crosby, described by Mellard 

 Reade. The volume has been carefully prepared, and 

 is a valuable and interesting record of the work of 

 Liverpool geologists. 



Catalogue of the Lepidoptera Phalaenae of the British 

 Museum. Vol. ix. Catalogue of the Noctuidae in 

 the Collection of the British Museum. By Sir 

 George F. Hampson, Bart. Pp. xv + 552; plates 

 cxxxvii-cxlvii. (London : Printed by Order of the 

 Trustees British Museum [Natural History] ; Long- 

 mans and Co.; B. Ouaritch ; Dulau and Co., Ltd., 

 1910.) Catalogue 155. ; plates, 125. 

 We have again to congratulate the authorities of the 

 British Museum and the indefatigable author on the 

 appearance, within less than a year, of another 

 volume of this highly important descriptive cata- 

 logue of moths. It is the sixth which has been 

 devoted to the Noctuidae, and is the third and last 

 i'olume dealing with the great subfamily Acronyctinae, 

 of which 385 genera and 2288 species (a large propor- 

 tion new) are described, and a great number illus- 

 trated in the three volumes devoted to the subfamily. 

 It may be useful to note that at the commencement 

 of his work Sir George gave a table of fifty-two 

 families of Lepidoptera, of which seven (families 

 33-39 inclusive) are butterflies, placed between family 

 32, Castiniadae, and family 40. Euschemonidae, the 

 remaining forty-five families being moths. Of these, 

 the first three, the Syntomidae, Arctiadae, and Agaris- 

 tidae, are described in the three first volumes of 

 the work ; while of the fifteen subfamilies into 

 which the Noctuidae are divided at the commence- 

 ment of vol. iv., only the first four subfamilies 

 have vet been dealt with. It therefore follows that 

 the nine volumes which have hitherto appeared can- 

 not be expected to represent a quarter, and perhaps 

 not even a tenth, of the whole work, although 



