November 28, 1895] 



NATURE 



77 



pressure) a quantity of the dimensions of force divided 

 by area ; but, after all, we have had to put up with 

 ambiguities of this kind for so long, that the matter is 

 of no great consequence to the class of readers for whom 

 ' Prof Tait's useful little book is intended. G. H. B. 



OUR BOOK SHELF. 



The People of the Moon. By Tremlett Carter. Pp. 402. 

 (London : The Electrician Printing and Publishmg 

 Co., Ltd., 1895.) 



This remarkable book bears upon every page evidence 

 of scientific knowledge and vivid imagination. It is 

 not simply a story of a journey to our satellite — that idea 

 has been worn to threads since Jules Verne used it for 

 the ground-plan of his novel — but purports to be a trans- 

 lation of a volume written by a lunar inhabitant, and sent 

 to the earth. More than one ingenious individual has 

 sapiently suggested that the side of the moon remote 

 from us is inhabited ; and as we are not likely to obtain 

 any information on the matter, every one is free to indulge 

 in that belief. The idea that there are living beings in 

 the moon's interior, is of a similar harmless character, 

 and the author of this book has made the most of it. 



Down in the interior of the moon, and near the centre, 

 dwelt a race of people — the Sarava — who believed that 

 the universe was an illimitable extent of solid rock, 

 honeycombed throughout with endless tunnels and 

 caverns. But a man arose — a lunar Copernicus — who 

 propounded the doctrine that the place which the 

 Sarava occupied was merely a lump of cavern-hollowed 

 rock suspended in an infinite vacant space. Urged by 

 a'vision, a Prince of the Sarava sets out with two com- 

 panions in the hope of reaching the surface, and their 

 expedition is successful. With the adventures of the 

 explorers, we have nothing to do, nor is it for us to 

 analyse the sentimental undercurrent. The attractive 

 parts of the story, from the scientific point of view, are 

 those which show the author's acquaintance with electro- 

 magnetic waves and the ether. He makes the Sarava 

 possess machines to etherealise matter, so that by 

 having two powerful electromagnetic foci at any dis- 

 tance apart, it was possible to transmit objects or people 

 from one to the other with the velocity of light ; the 

 object being etherealised at one focus, projected to the 

 other, and then by a similar series of electromagnetic 

 waves converted into its material state. Having reached 

 such a high state of knowledge of the ether, it is hardly 

 necessary to say that the Sarava could see and speak 

 with one another at a distance, without the necessity 

 of connecting wires, and had also managed to tap the 

 ether and use its terrific energies in destructive weapons. 

 How very intelligently, and with what regard to known 

 facts these imaginary machines are constructed, can only 

 be appreciated by a perusal of the book. We congratu- 

 late the author on the skilful and original way in which 

 he has handled an old subject. 



Frail Children of the Air. Excursions into the World 

 of Butterflies. By Samuel Hubbard Scudder. Pp. 279. 

 Nine plain plates. (Boston and New York : Houghton, 

 Mifflin, and Co. London : Gay and Bird, 1895.) 



It might be supposed from the title of this book, that 

 it was wholly popular, and that entomologists would find 

 little to attract their attention in it ; but this would be a 

 great error, for it is really a collection of thirty-one 

 philosophical essays on butterfly and caterpillar life, 

 reprinted, with additions and modifications, from Dr. 

 Scudder's great work on the " Butterflies of New 



KO. I 36 I, VOL. 53] 



England." Many subjects of great interest and import- 

 ance are touched upon, relative to the modes of pro- 

 tection of butterflies m all their stages : fossil butterflies ; 

 the origin of the present butterfly fauna of North 

 America ; the habits of butterflies, caterpillars, &c. One 

 of the most interesting chapters is, perhaps, that relating 

 to the butterfly fauna of the White Mountains of New 

 Hampshire, where butterflies appear to swarm to an 

 extent which the richest localities in Europe could perhaps 

 hardly parallel in number of individuals. Dr. Scudder 

 does not confine his remarks to American species, how- 

 ever, but has also looked up the European literature 

 bearing on his subject very thoroughly, as, indeed, was 

 only to be expected from an entomologist of his industry 

 and energy. Here and there, however, we may detect 

 a casual oversight, as where Iphiclides podalirius, L., is 

 spoken of as "confined to the Mediterranean region" 

 (p. 247), when it is really found throughout the greater 

 part of Central Europe as well. Occasionally, too, Dr. 

 Scudder's information can be supplemented, as when in 

 speaking of ants attending the larvae of Lycccnida; he 

 omits the instances which have been recorded of some 

 Australian species {Hypochrysops delicia, Hewitson, 

 and lalmenus evagoras, Donovan, &c., see Anderson and 

 Spry's " Victorian Butterflies," pp. 94, 98, 99). Incident- 

 ally various subjects of more general interest are remarked 

 upon, as where Dr. Scudder agrees with Desor (p. 250) 

 in attributing the greater intensity, both of butterfly and 

 of human life in America, as compared to Europe, to the 

 much greater vicissitudes of climate in the former 

 country ; or when, in more than one passage, he agrees 

 with Wallace and others, among our deeper-thinking 

 naturalists, that the workings of natural selection are 

 incomprehensible unless we regard them as guided by a 

 controlling intelligence. W. F. K. 



The Story of the Earth' in Past Ages. By Prof H. G. 



Seeley, F.R.S. Pp. 196. (London : George Newnes, 



Ltd., 1895.) 

 Prof. Sekley tells the geological story of the earth in 

 an orderly, though not strikingly luminous, manner. 

 Beginning with evidence of the earth's internal heat, he 

 passes to the materials of mountain chains, and then to 

 the consideration of volcanic rocks. With reference to 

 the latter section, it seems to us that his descriptions of 

 the compositions of rhyolites, trachytes, andesites, and 

 basalts are more suitable for a text-book than for a book 

 intended for popular reading. In fact, Prof Seeley has 

 too exalted an idea of the knowledge of the general 

 public, who, we are afraid, will not be able to understand 

 a large part of his little book. Few of his unscientific 

 readers will have any idea conveyed to them by remarks 

 such as follow : " The bivalve shells are usually species 

 of Cyclas, or Unio, or Ajiodonta. The univalve shells 

 are either the pond shells Planorlns, Paludina, and 

 Limna'a, or such river shells as Neritina, and the fresh- 

 water limpet." Similar instances of the use of technical 

 nomenclature without explanation could be quoted from 

 almost every chapter in the book. 



The materials of stratified rocks form the subject of 

 the fourth chapter, and then, after short descriptions of 

 the succession of strata, the origin of stratigraphical 

 geology, and fossils, the formations are treated in order, 

 from the Archaean rocks to glacial deposits and gravel 

 beds. Within the compass of less than two hundred 

 small pages, it has only been possible for Prof Seeley to 

 indicate a few of the features of the different rocks. 

 Thus, the chapter on Archaean rocks consists of three 

 small pages, and would only fill about a column of 

 Naturk, and there are other chapters just as scanty. 

 Most of the figures are very badly reproduced, and there 

 is no index ; so that, altogether, we do not regard the 

 book as a very satisfactory one. 



