July 28, 1881] 



NA TURE 



283 



OUR BOOK SHELF 



Practical Botany for Elementary Students. Introductory 

 to the Systematic Study of Flowering Plants. By D. 

 Houston, Science Master, South London Middle-Class 

 School Association. (London: W. Stewart and Co., 

 1881.) 

 This book differs from Mr. Bettany's (vol. xxiv. p. 235) in 

 being less general in its treatment. It is in fact a series of 

 studies of the coarse anatomy of a number of common 

 plants much on the plan first given in Huxley and Martin's 

 " Elementary Biology." Each study is followed by a 

 technical description, notes on the distinctive characters 

 of a few allied plants, and some miscellaneous matter. 

 " The plants selected are well-known and easily-pro- 

 cured types of the fifteen natural orders included in 

 the .Syllabus of the First Stage of Elementary Botany 

 issued by the Science and Art Department, as it is 

 behaved that no better selection of natural orders, in- 

 tended as introductory to the study of classification, could 

 possibly be made." As far as can be judged without 

 working through it, the book is well done, and will be a 

 valuable aid to the teacher if honestly used. Mr. Bettany's 

 plan of teaching the art of describing is soundest. His 

 book can hardly be abused, while with Mr. Houston's 

 there is the risk that incompetent teachers may make 

 their pupils simply learn a large part of it by heart, on the 

 chance of one or more of the plants being set in an exa- 

 mination. Occasionally, where the author abandons the 

 sure ground of personal study, he makes slips. Thus 

 more than half the short list of exotic genera of orchids 

 has the names misspelled. The distribution in time and 

 space of the several orders illustrated is given, though 

 somewhat meagrely. Perhaps in the present state of 

 pateophytology the former is not very important. Under 

 Orehidacecp, for example, the Distribution in Time is given 

 as " not represented," which, apart from the fact that it is 

 a contradiction in terms, means nothing more than that 

 fossils referable to this group of plants have not been 

 found, and are perhaps not likely to be. It may be asked, 

 too, what is the value of the evidence upon which the 

 liliaceous genus Yucca is dated back to the Trias ? 



Von den Umwdhungen iin Weltall. Von Rudolf Falb 



(Vienna, Pesth, and Leipzig: Hartleben, 1881.) 

 This work is divided into three parts, with separate head- 

 ings : (i) In den Regionen der Sterne ; (2) Im Reiche der 

 Wolken ; (3) In denTiefen der Erde. The author, whose 

 name has frequently been mentioned in our columns, has 

 lectured in various German cities on volcanic and cosmo- 

 logical phenomena, and eventually went to South America 

 in order to study the great volcanoes of the Cordilleras. He 

 conceived an earthquake theory, and his South .American 

 friends induced him to publish it. The result is the book 

 now before us, which was published in Spanish at Val- 

 paraiso as far back as 1877 (" Estudio sobre los templores 

 de tierra fundado en la historia del universe "). After a 

 sojourn in South America extending over three years, 

 Herr Falb returned to Europe, and his earthquake theory 

 was frequently mentioned in the press in connection with 

 the Agram earthquakes. The theory is simple enough in 

 itself, and the author has at least the credit of being most 

 enthusiastic in its support and in adducing as many facts in 

 proving the same as can possibly be found. Whether he 

 succeeds in proving it is another question. According to 

 Herr Falb's view, all earthquakes, or at least by far the larger 

 majority of earthquakes, are of a volcanic origin ; or, to 

 express it concisely, "earthquakes are subterraneous 

 eruptions." The basis of this theory is naturally the 

 supposition that the whole interior of the earth is an 

 ocean of incandescent matter. This is affected by the 

 attraction of sun and moon in exactly the same manner 

 as the sea and atmosphere are acted upon. The second 

 division of the book therefore represents sun and moon 



as the generators of storms and tides ; and in the third 

 division, the principal one, we see the cause of earth- 

 quakes traced to the influence of sun and moon. There 

 is no doubt that the author has a special gift of repre- 

 senting his subject clearly and popularly ; his eloquence 

 keeps the reader interested from the first line to the last. 

 He quotes no less than thirty facts, from which he draws 

 thirteen dift'erent inferences in proof of the volcanic 

 nature of earthquakes. We regret that space does not 

 permit us to enter further into details, but we can heartily 

 recommend the book to our readers. 



The Quantitative Estimation of Phosphoric Acid. By 



M. H. Joulie. Translated by J. Barker Smith. 



(Dulwich : Published by the Author, 1881.) 

 The laudation of M. George Ville, with which the trans- 

 lator opens his preface, discouraged us at first from 

 further perusal of this pamphlet on the citro-uranic 

 method of determining phosphoric acid in manures ; 

 and when we did peruse these sixty pages, our chief im- 

 pression was derived from the comical literality with 

 which French idioms had been rendered into English 

 words. But after all a good many useful hints may be 

 gathered by practical analysts from this little book. Of 

 course most agricultural chemists are familiar with the 

 difficulties which beset the fair sampling and preparation 

 of manures for analysis, and they are also acquainted 

 with many special contrivances for overcoming these 

 difficulties. But information as to new and improved 

 methods of operating, and as to modifications of old 

 processes, is always acceptable. 



The essence of M. Joulie' s method consists in the 

 precipitation of the phosphoric acid in a prepared solu- 

 tion of a manure by means of a solution containing 

 citrates of ammonium and magnesium. The precipitate 

 which forms is thus produced in the presence of the lime 

 as well as of the iron and alumina of the original liquid : 

 we should like further proof that the whole of the phos- 

 phoric acid is invariably precipitated under the conditions 

 described by M. Joulie, especially as he directs the solu- 

 tions, if rich, to be kept no more than two hours before 

 the ammonio-magnesian phosphate is filtered off. The 

 second and final stage in M. Joulie's method is the solution 

 of the precipitated phosphate and its titration by a standard 

 solution of uranium nitrate. 



The second part of this pamphlet describes the treat- 

 ment of manurial phosphates with solutions of ammonium 

 oxalate and ammonium citrate in order to determine their 

 "relative assimilability." We are not aware that M. 

 Joulie was the first to employ these reagents in the 

 analysis of phosphates — his announcement of the use of 

 the oxalate being in 1872, and of the citrate during the 

 next year. Anyhow, we must demur to some of the con- 

 clusions which M. Joulie draws from his experiments, nor 

 can we accept as satisfactory the final directions for the 

 " assay of superphosphates" with which the last fifteen 

 pages of his manual are occupied. The determination of 

 the phosphoric acid and phosphate dissolved by distilled, 

 or, if you will, carbonated water, from a superphosphate 

 cannot be safely replaced by a determination of the phos- 

 phates soluble in ammonium citrate. For we lack proof 

 that retrograded phosphates are equal in value with mono- 

 calcic phosphate, which alone possesses an initial diffusive 

 power when it is introduced into the soil. 



The Butterflies of Europe. Illustrated and described by 

 Henry Charles Lang, M.D., F.L.S. Part I. (L. Reeve 

 and Co., 1S81.) 

 We have received Part I. of this work, the approaching 

 publication of which was announced in these columns a 

 few weeks back. The whole of the species (and some 

 prominent varieties, &c.) inhabiting Europe proper will 

 occupy about twenty monthly parts, each containing six- 

 teen pages of text and four coloured plates. The plates 



