September 19, 1907] 



NA TURE 



515 



that contain oolitic grains, and are perhaps of marine 

 origin. No economic products of great importance are 

 known, tliough ores of copper, iron, and manganese 

 have been found, and it is suggested that gold should 

 be sought for. 



It onlv remains to add that the work is well printed 

 and illustrated. If the geological maps are exception- 

 allv ruddy in tint, this arises from the extent of igneous 

 rocks. For the topographical details the author ex- 

 presses his indebtedness to Mr. H. G. Si-till, who con- 

 tributes also an appendix on meteorology. The photo- 

 graphic views enable the reader to gain a good idea 

 of the scenery and rock-features, as well as of a 

 hya^na-den, of certain stone-circles, and of the Sinai 

 convent. H. B. W. 



ELECTROCHEMISTR Y. 

 A Text-book of Electro-chemistry. By M. Le Blanc; 

 translated by VV. R. Whitney and J. W. Brown. 

 Pp. xiv+338. (London : Macmillan and Co., Ltd , 

 1007.) Price loi. 6d. net. 



THE new English edition of Le Blanc's " Electro- 

 chemistry " has followed very closely upon the 

 publication of the fourth German edition. One is at 

 once struck by the great increase in size of the book 

 and by the large increase in the number of diagrams. 

 From the translators' preface we notice that twenty- 

 five of the diagrams have been added by themselves, 

 and the book has certainly been improved by the 

 additions. 



.Although the scheme of the book is much the same 

 as it originally was, tlie additions are so numerous 

 that it is almost a new work. By studying this edition 

 and the first edition, wliich appeared in 1S95, one is 

 struck by the large amount of work which has been 

 done in the domain of electrochemistry, albeit the 

 fundamental laws have undergone very little change, 

 the chief being one of degree rather than of 

 principle. The ionic theory has been assailed from 

 all sides, but although certain modifications have 

 been made, such, for example, as the conception of the 

 hydration of the ions, it must be conceded that it has 

 rather gained strength than lost by the attacks. If 

 tho-o who assail the theory would give an alternative 

 hypothesis which would as satisfactorily explain the 

 phenomena of solution as does the ionic hypothesis, 

 then the arguments would assume a more tangible 

 form, and the ionic theory might be consigned to the 

 limbo of histor}'. 



Prof. Le Blanc deals almost entirelv with the theo- 

 retical aspects of electrochemistr)', but at certain points 

 he indicates the bearing of theory on practice. For 

 example, on p. iS, when referring to the conver- 

 sion of heat into electrical energy and of electrical 

 energ>' into heat, a digression upon the " Electrical 

 Furnace and its Industrial Importance " is made, the 

 application of Ohm's law being given. Brief reference 

 is here made to calcium carbide, cyanamide, carborun- 

 dum, phosphorus, and the preparation of nitrates from 

 atmospheric nitrogen, but the book, as already men- 

 tioned, does not deal with technical processes. 



Chapter ii. deals with the development of electro- 

 NO. 1977, VOL. 76] 



chemistry up to the present time, and treats in the 

 main with the development of the ionic theory. 



More notice might have been taken of the difficult 

 subject of the electrolysis of fused salts, the author 

 having contented himself with a footnote on p. 316 

 referring the reader to Lorenz's " Die Elektrolyse 

 geschmolzener Salze," and a remark that the pheno- 

 mena are entirely analogous to those of aqueous solu- 

 tions. The interesting phenomenon of electrolysis 

 without electrodes is referred to on p. 317, and it 

 is pointed out that in this case, as in electrolysis where 

 both electrodes dip into the solution, Faraday's law is 

 obeyed. 



The translators, Drs. Whitney and Brown, have paid 

 particular attention to noinenclature, and have en- 

 deavoured to be consistent throughout. The method 

 adopted is set out in full in an appendix. The adoption 

 of F instead of E for electromotive force is hardly 

 happy; according to this rendering we get Ohm's law 



-,•;■ 



F is more generally used to denote a Faraday, or 

 96,540 coulombs of electricity. The translators employ 

 the symbol Q for quantity of electricity. These are, 

 of course, minor points, but they are inclined to 

 muddle the student. It would perhaps be a good thing 

 to convene an international committee so that elec- 

 trical .-nd electrochemical nomenclature might be 

 standardised ; at present it must be admitted that it is 

 more or less chaotic. 



From a theoretical standpoint we do not think it 

 possible to meet with a better book than the one 

 before us, and there is little doubt that it will be 

 highlv appreciated and widely studied. F. M. P. 



AUSTRALIAN INSECTS. 

 Australian Insects. By Walter W. Froggatt, Govern- 

 ment Entomologist, New South Wales. Pp. xiv + 

 449; with 37 plates, containing 270 figures, also 

 180 text-blocks. (Sydney : William Brooks and Co., 

 Ltd., 1907.) Price 12s. 6d. 



THIS is the first general introductory work pub- 

 lished on the insects of .Vustralia, and it will be 

 very useful to residents commencing the study of 

 entomology, as well as to any European or .American 

 entomologists who wish for a general view of the 

 .Australian insect fauna, which contains a large 

 number of highly interesting forms not met with in 

 other parts of the world, though som.e species found 

 in the extreme north appear to be onlv an offshoot 

 from the rich tropical fauna of New Guinea. 



The classification adopted is mainly that employed 

 by Dr. D. Sharp in the " Cambridge Natural 

 History." Mr. Froggatt commences his work 

 with an introduction, tables of contents, and chapters 

 on classification, distribution, structure, and fossil 

 insects ; after a detailed account of the principal 

 groups of insects represented in .Australia, including 

 much interesting information about habits, &c., he 

 concludes the book with chapters on the collection 

 and preservation of insects, museum collections and 

 types, publications dealing with .Australian entomology, 

 and an alphabetical index of Latin and English i?-ime)i 



