May 25, 19 1 6] 



NATURE 



259 



guidance " to others. We have noted quite a 

 number of points Hke this, but it would be a 

 waste of time and space to refer to them in detail. 



(2) " It is the desig-n of this book to furnish 

 guidance " to the "college student " and to "those 

 who are pursuing a correspondence course " " in 

 the solution of engineering problems." The 

 nrst forty pages or so contain a resume of the 

 mathematical and trigonometrical formulae likelv 

 to be required. This is certainly useful, but much 

 of it should not be necessary to students whose 

 mathematical attainments are sufficient to follow 

 the methods employed in the book, which make 

 free use of the calculus, and seem to prefer pure 

 trigonometrical solutions to those obtained with 

 the help of vectors. Then follow a number of 

 definitions concerning alternating quantities and 

 elementary electrical matters. The uninitiated 

 reader should be warned that some of these give 

 quite a different meaning to certain terms from 

 that current in this country, and others, if strictly 

 interpreted, do not express quite what the author 

 presumably intended. The book, however, is not 

 intended as a text-book, but as a book of ex- 

 amples, and if the student conscientiously works 

 through all the examples and problems given, 

 he can scarcely fail to gain a fair insight into 

 alternate current theory. 



(3) The amateur or student who wishes to make 

 a small transformer for himself will find the con- 

 struction of the little one described in this book 

 well within his powers. The type chosen is the 

 Faraday ring type, which is an efficient type for 

 its size, and is suitable for making with some- 

 what limited resources as to tools. The type 

 does not, however, lend itself to cheap factory 

 construction, and the book is not intended for 

 electrical engineers. D. R. 



AX AMERICAN GARDENING BOOK. 

 My Groiving Garden. By J. H. McFarland. 

 Pp. xiii + 216. (New York: The Macmillan 

 Co.; London: Macmillan and Co., Ltd., 1915.) 

 Price 85. 6d. net. 



T T is the better sort of intellectual morality 

 ^ which has inspired the writer of "My Grow- 

 ing Garden." As its title suggests, it begins 

 ah initio, almost in principio, and the whole book 

 bubbles over with the enthusiasm of the genuine 

 gardener who creates, aspires, and sometimes 

 has to stoop to conquer. The shrewd common 

 sense that underlies some of the passages, which 

 a meticulous critic might perhaps describe as 

 otherwise florid, has a pleasant American char- 

 acter, and gives the book a quality of its own. 



It is quite possible that the English garden- 

 lover may not be able to extract many special 

 "wrinkles" from Mr. McFarland 's book, but he 

 will most surely derive a good deal of pleasure 

 from an acquaintance with the American garden 

 as it has developed under the care of an American 

 enthusiast. The chapter on weeds is especially 

 a pleasant one, and, indeed, the whole book is 

 well worth the reading. 



NO. 2430, VOL. 97] 



One of the oddly deep-rooted tendencies that 

 Adam has transmitted to his descendants is a 

 love of the garden. Like other tendencies, it may 

 be latent in some, but is continually cropping up 

 after the fashion of other primal instincts. Now 

 and again it bursts into widespread activity, which 

 is perhaps more than genuine; for imitation, a 

 pre-Adamite simian character, plays no small part 

 in the ostensible development, mental, moral, and 

 otherwise, of gregarious folk. One of the accom- 

 panying features of the present epoch, symp- 

 tomatic, perhaps, of the proselytising spirit of 

 aggressive humanity, is apparent in the multitude 

 of books on gardens which have, for the last 

 decade or so, been rolling so tumultuously from 

 the printing press. The future student of our 

 times might do worse than give his attention to 

 this oddly mixed literature. It has been written 

 by and for all sorts and conditions of men — and 

 women — and it reflects, as the serious, fictitious, 

 or mercenary pursuit of a widely cultivated hobby 

 can do so well, a wide range of human aspiration 

 — a curious mixture of noble metal i.nd worthless 

 clay. J. B. F. 



OUR BOOKSHELF. 



Elements of Mineralogy. By F. Rutley. Revised 

 by H. H. Read. Nineteenth edition. Pp. xxii + 

 394. (London : T. Murby and Co., 1916.) Price 

 3s. 6d. net. 

 L\ this nineteenth and extensively revised edition 

 of Rutley 's "Mineralogy" the general arrange- 

 ment of the original has been largely retained, 

 but such changes have been made as the reviser 

 has thought necessary "to bring the book into 

 line with modem tendencies in economic mineral- 

 ogy, and to make it an introduction to the scien- 

 tific prospecting and determination of mineral 

 deposits." 



Occurrence and origin are treated more fully 

 than in former editions, also the uses of the indus- 

 trial minerals, and the geographical location of 

 important deposits. An interesting introduction 

 has been contributed by Mr. G. T. Holloway, and 

 a series of excellent paragraphs prefatory to the 

 several useful and precious metals by Mr. W. G. 

 Wagner. A serviceable glossary of terms used in 

 economic geology has been added by the reviser. 



Typographical errors are few, but errors of 

 matter numerous. The composition of anorthite 

 is given as CaO.ALOg.GSiOo (p. 191) : it is stated 

 of orthorhombic crystals (p. iii) that "all sections 

 give straight extinction " ; aegerine and wollaston- 

 ite are classed with the aluminous pyroxenes (p. 

 198), and riebeckite with the aluminous amphiboles 

 (p. 206). Style, and precision of language, too, 

 are often defective. The tetragonal system is char- 

 acterised by "two equal lateral axes, one unequal 

 vertical axis" (p. 71); the optic axes of biaxial 

 crystals are described as directions "along which 

 light can travel with equal velocity " (p. gq) ; the 

 Mond process is said to produce " nickel in a great 

 state of purity" (p. 338); we are told (p. 116) 

 that "iron carbonate (FeCO,) is the mineral 

 chalybite," and (p. 376) that platinum is used "in 



