74 



NA TURE 



[Nov. 22. 1883 



sulphuretted hydrogen. The white felting wh'ch gives the 

 name " white " is formed by threads of different species 

 of Beggiatoa, a thread-like fungus classed with the 

 Schizomycetes by Zopf and others who have stated that 

 bacteria forms constitute a stage of their life-cycle. Thus 

 Monas Okenii, Bacterium siilphuratiim, Clathrocystis 

 rosea persici)!a, and Beggiatoa rosea-persicina have all 

 been described as stages of a single life-history. Dr. 

 Englcr is extretnely cautious on this point, and limits 

 himself to what he has seen. He does not agree with 

 Warming that Monas Miillcri, which occurs with the 

 Beggiatoae, is the young stage of one of them ; although 

 he has observed one species sending off motile spherical 

 spores. Two new genera of thread-shaped fungi are de- 

 scribed which were found on a Caiiniianis locusta living 

 on the white bottom. The paper is illustrated by a 

 number of admirably executed drawings. 



Thus the volume forms a very considerable contribu- 

 tion to the accurate scientific knowledge of the Baltic, for 

 the attainment of which the Commission was instituted. 

 Like all the other work published by the Commission, it 

 exemplifies in the most convincing manner the truth that, 

 to obtain light on marine problems, what is required is 

 not a mass of evidence from people all equally without 

 knowledge on the subject, but continued and elaborate 

 research. 



MASCART AND JOUBERT'S ''ELECTRICITY 



AND MAGNETISM" 

 Electricity and Magnetism. By E. Mascart and J. 



Joubert. Translated by E. Atkinson. Vol. I. (London : 



Thos. de la Rue and Co., 1883.) 



WE took occasion some time ago to draw the atten- 

 tention of the readers of Nature to the "Lecjons 

 sur I'Electricitd et le Magn^tisme," by Professors Mascart 

 and Joubert ; we have now to thank Prof. Atkinson for 

 an English translation of this valuable work. This is 

 not the place to inquire into the necessity for an English 

 translation of any Erencii scientific work, not to speak of 

 one which makes such demands on the culture of its 

 readers as this docs. It is enough for us to know that 

 the publishers and translator consider the number of 

 semi-educated Englishmen sufficiently great to justify 

 their venture ; it is our part to speak to the merits of the 

 work and the manner of the translation. 



The alterations in the matter of the book are so slight 

 as to call for no remark. Our first duty therefore reduces 

 itself to a simple iteration of our high opinion of its value 

 as a scientific manual. At the present time the public is 

 well supplied with scientific instructors. The good inten- 

 tions of all of them need not be doubted; but the inac- 

 tivity or modesty of some and the incompetency of others 

 have brought it about that there are large gaps in our 

 repertory of science text-books either not filled at all or 

 filled very unworthily. It would not be accurate to say 

 that vol. i. of the treatise of Mi\I. Mascart and Joubert 

 fills the greatest of these gaps \n the department of elec- 

 tricity and magnetism ; nevertheless it fills a place not at 

 present wholly occupied by any English te.\t-book of 

 merit. It has the misfortune, no doubt, of overlapping to 

 a large extent the gre <t work of iNIaxwell ; but we believe 

 that the tyro in the mathematical theories of electricity 



and magnetism will find it of the greatest advantage to 

 use Mascart and Joubert as companion and commentary 

 to Maxwell's volumes. In all that relates to fundamental 

 points and general theory Maxwell should be studied, 

 even where he is hardest to follow, because his work was 

 written, not to evade, but to meet, difficulties. On the 

 other hand, Mascart and Joubert will be found invaluable 

 in matters of detail. We know of no text-book in any 

 language that contains such an abundance of elementary 

 illustrations of electrical and magnetic theory, all arranged 

 with an elegance peculiarly French. 



The English version now before us is neatly printed 

 and solidly got up. The translation on the whole is very 

 well done. It would be easy to pick out small inaccuracies 

 here and there, particularly in the early chapter. For 

 some of these the translator is not altogether to blame ; 

 for the introductory part of the work seems to us to be 

 less clear and carefully written than the following chapters, 

 where the authors enter more into detail ; and in that part 

 of the book the translation leaves little to be desired. We 

 noticed very few misprints, but one calls for correction : 

 the name of van Troostwyk's collaborateur in the decom- 

 position of water by the voltaic current was Deimann and 

 not Diemann. No doubt this mistake occurs in the 

 original ; but the individual in question, though perhaps 

 not widely known, yet deserved better than to be made 

 quite unrecognisable. This brings to mind the only com- 

 plaint of any gravity we have to bring against the editor 

 of the English translation. Why did he not do some- 

 thing to remedy the one serious defect of MM. Mascart 

 and Jouberl's text-book, viz. the want of sufficient refer- 

 ences to original sources of information? It must be 

 remembered that the scientific student who goes the 

 length of MM. Mascart and Joubert's leading strings is 

 expected one day to walk alone ; and some indication 

 should be given him of the paths that lead to farther 

 knowledge. A defect of the kind might be overlooked in 

 a school primer, written to enable the oppressed school- 

 master to screw a Government grant on the minimum 

 qualification from some reluctant inspector, but is to be 

 deplored in a work of the present pretensions. 



Instead however of complaining farther of what MM. 

 Mascart, Joubert, and Atkinson iiave not done (perhaps 

 had not the leisure to do) for us, it will be more fitting to 

 conclude by thanking them heartily for what they have 

 done, and done so well. G. C. 



OUR BOOK SHELF 

 Energy in Nature. By William Lant Carpenter, B.A. 



B.Sc. (London, Paris, and New York : Cassell and 



Co.) 

 This book is, with some additions, the substance of a 

 course of six lectures on the Forces of Nature, and their 

 mutual relations, delivered under the auspices of the 

 Gilchrist Educational Trust. 



It is of the greatest importance that the general body 

 of the people, and more especially the intelligent artisan 

 class, should become acquainted with the leading prin- 

 ciples of the science of energy. The series of lectures 

 delivered with this object represents one of the best 

 sustained efforts to bring this great subject before the 

 minds of this class of the people, and in collecting 

 together and publishing these lectures the author has 

 done a work which must be regarded as a scientific boon 

 to the artisan. 



