160 



KNOWLEDGE. 



[July 1, 1895. 



The Source and Mode of Solar Enerrm tliroiiqhout the 

 Uyiiverse. By J. W. Heysiuger, M.A., "M.D. Pp. 361. 

 (Philadelphia : -T. B. Lippincott Co.) i^a.OO. So far as 

 we understand the author of this volume, his theory is 

 that electric currents are constantly passing through 

 attenuated aqueous vapour between the sun and planets, 

 and decomposing it into its constituents. Hydrogen is 

 given off at the solar electrode and oxygen at the terres- 

 trial or planetary electrode. We thus have an explanation, 

 which may be left to our readers to assess at its proper 

 value, of the preponderance of oxygen in our own atmos- 

 phere and of hydrogen in the sun. The electric currents 

 required hy the theory are supposed to be generated by the 

 rotation and revolution of the planets, which are regarded 

 as playing the part of electrical induction machines. Dr. 

 Heysinger extends this fantastic idea to all astronomical 

 phenomena, and uses it as a master-key to unlock, in a 

 fashion, the caskets of celestial mysteries. In support of 

 his views, he quotes copious descriptions from the works 

 of eminent writers, few of whom, however, would care to 

 give countenance to the curious theory in connection with 

 which their writings are used. 



A Handbook of Systematic Bot.inij. ByDr. E. Warming. 

 Translated by Prof. M. C. Potter, M.A., F.L.S. (Swan 

 Sonnenschein & Co.) As a text-book of botany, this will 

 take a high place, and as a handbook of reference it will 

 prove valuable, though some of the lower groups of plants 

 are but cursorily dealt with. The translation is from the 

 third Danish edition of Prof. Warming's " Handbog i den 

 Systematiske Botauik," and from Dr. Knoblauch's German 

 edition. The order of treatment in the present volume 

 is Thallophyta (subdivided into Myxomycetes, Alga' and 

 Fungi), Muscinese (Mosses), Pteriodophyta, Gymnospermaj 

 and AngiospermiE. The Algte and Fungi have been revised 

 and rearranged in co- operation with Dr. Knoblanch. The 

 sequence of orders in the Angiosperms, being that of the 

 original Dan-'sh edition, wUl be unfamiliar to J']nglish 

 students, but it possesses advantages over the more artificial 

 system generally adopted. Prof. Potter states, in an 

 appendix, the chief systems of classification of plants from 

 Eay (170B) to Engler (1H92), and shows how the artificial 

 systems into which members of the vegetable kingdom 

 have been arranged have gradually developed into natural 

 systems, founded upon mutual relationships. The volume 

 is richly illustrated, and is altogether a serviceable text- 

 book for students of botany. 



The FArments of Botany. By Francis Darwin, M.A., 

 F.E.S. Pp. 235. (Cambridge : University Press.) Here 

 we have a book which is a model of what an elementary 

 science manual should be. The student who uses it will 

 feel that he must see for himself the structures of the 

 plants described, and personally verify the phenomena they 

 illustrate. The fourteen chapters of the book contain the 

 substance of the botanical lectures given to medical 

 students in the course of elementary biology at Cambridge, 

 and the practical work done in connection with the 

 lectures is described in an appendix. Departing from the 

 usual method, the author, instead of using a small number 

 of species to illustrate the morphology, physiology, and 

 natural history of plants, fixes on certain facts and 

 phenomena, and selects a number of plants to exemplify 

 them. Too great praise cannot be given to the numerous 

 illustrations, which have mostly been drawn from Nature, 

 and are far in advance of the stock figures that occur in so 

 many text-books. Indeed, both text and illustrations are 

 so attractive that the student who uses the book will 

 certainly have a love of botanical knowledge developed in 

 him. 



Crystalloriraphi/ : a Treatise on the Morpholnyy of Crystals. 

 By Prof. N. Story Maskelyne, M.A., F.K.S. Pp. 521. 

 (Clarendon Press.) 12s. 6d. Students of mineralogy have 

 long waited for this volume, and have wondered whether 

 the author would really complete his undertaking ; and 

 now the book has been published it fulfils the high expecta- 

 tions of all familiar with the work of the distinguished 

 mineralogist who is responsible for it. The treatise deals 

 solely with the morphology of crystals, that is to say, with 

 the characters which result from the distribution and 

 geometrical relations of their plane faces. It is a masterly 

 exposition, in which the subject is treated in the simplest 

 form compatible with strict geometrical methods. Students 

 with a limited knowledge of mathematics will be able to 

 comprehend some of the demonstrations, but the book 

 appeals more to those who have had a high mathematical 

 training. The volume undoubtedly ranks with the classical 

 treatises on crystallography. 



Annual Report of tlir Board of Bajucsts of the Smit/isonian 

 Institution, 1893. Pp. 762. (Washington : Government 

 Printing Office.) Not only are the operations and condition 

 of the Smithsonian Institution for the fiscal year ending 

 June 30th, 1893, described in this report, there is also a 

 general appendix comprising a miscellaneous selection of 

 papers from various publications, and embracing a wide 

 range of scientific investigation and discussion. Among 

 these memoirs we notice one on " The Great Lunar 

 Crater Tycho,'' by the late Mr. Eanyard, reprinted from 

 Knowledge. 



Geometrical Coyiics. By F. S. Macaulay, M.A. Pp. 260. 

 (Cambridge University Press.) Is. 6d. A well-constructed 

 and fairly complete treatise on the elementary properties 

 of conies, possessing clear descriptions, helpful illustra- 

 tions, and numerous examples. The principles and methods 

 employed are admirable. We commend the volume, which 

 is extremely well printed, to the notice of all teachers and 

 students of the subject with which it deals. 



Thin f/s New and Old; or, Stories from Enijlish Hisiori/. 

 Standard VI. By H. 0. Arnold - Foster. Pp. 218. 

 (Cassell & Co.) To the many excellent school-books which 

 Mr. Arnold-Foster has written must now be added this 

 volume, dealing with the Stuart period of English history. 

 Like the other volumes in the same series, this brings out 

 the realities of history in a manner calculated to arouse 

 interest in the minds of children. We are glad to see 

 that such an event as the fouudation of the Koyal Society 

 is not ignored, as it is in " drum and trumpet " histories 

 generally, and that the works of such men as Newton and 

 Harvey are not passed over in silence. 



BOOKS RECEIVED. 



Journal of the Franklin Institute fur Muij, 11595. 



First Principles of Chemistry. By Samuel Couko, JI. A. (Creorgi' 

 13cll & Sons.) 2s. (id. 



mudents Practical Cheitiistri/ Test Tables and Qunlitatire 



Analysis. By Samuel Cooke, M.A. (George Bell & .Suns.) Is. 



First Principles of Astronv/nij. \iy Samuel Cooke, M.A. (Creorge 

 Bell & Sous ) Is. fid. 



Lessons in Flementary Physics. Sy Balfour Stewart, M.A., (ie. 

 (Maemillan & Co.) 4s. tid. 



Fiir/erprint Directories. Bv Fiaucis tralton, F.B.S. (Maemillan 

 & Co.) 



Object Lessons in Botany. Book II. By Edward Snelgrovc, B..V.. 

 (.Farrold & Sons.) .33. 6d. 



A First Book of Flectriciti/ and Maynetism. B\ W. I'eri'i'ii 

 Mayeoek, M.I.K.E. (Wliittaker & Co.) 2s. tid. 



Acoustics of Public Buildings. By T. Koger Smith. (Cru5li\ 

 Loekwood & Son ) Is. (id. 



Proceedinys of the Academy of Xutural !Scien<-es, Philadc'phia. 



