390 



NATURE 



[Augtist 2 2, 1669 



simply expresses the properties of a compound, but it 

 would be difficult to say what properties are indicated by 

 such formulae as that referred to. 



There are a few statements on important subjects that 

 at the present time concern no one but the historian. 

 For example, the classification of salts as normal, acid, or 

 basic, according to the proportion between " the bonds of 

 the acid radical " and " the bonds of the basic radical," was 

 never generally accepted, and is now universally allowed 

 to be an altogether faulty method. The extraordinary 

 prominence given to hydrogen dioxide or "free hydroxy 1," 

 which has four pages devoted to it, while sulphuric acid 

 has httle more than two, is scarcely justifiable, we think, 

 at the present time. But on the whole, the book is a 

 useful compendium of the principal properties of not only 

 the more important substances but also of many of the 

 compounds of the rarer elements. 



OUR BOOK SHELF. 



A Treatise on Geometrical Conies. By A. Cockshott and 

 Pev. F. B. Walters. (London : Macmillan and Co., 

 1889.) 



This work is not intended to supersede such works as 

 Besant and Taylor, which, being drawn up for University 

 students, naturally cover a good extent of ground, but 

 to meet what is a pressing need in school teaching. The 

 need of some recognized sequence of propositions, as our 

 authors state, has long been admitted. It was with a 

 view to meet this need, as we have previously stated in 

 this journal, that the Association for the Improvement of 

 Geometrical Teaching published its syllabus of the 

 subject, which had been accepted by the Association at 

 its annual meeting in January 1884. The work before 

 us has been drawn up in accordance with the syllabus, 

 the authors' aim being to invest the skeleton of the S)]labus 

 with suitable raiment. A main feature of the outline was 

 the prominence given to Adams's property (which boys 

 will call Adam's property), the S U K I (now changed 

 rightly, as O is used for the external point, to the S U O I) 

 proposition. In the parabola, we are told we may employ 

 the property in proving tangential propositions ; in the 

 case of the ellipse and hyperbola, the authors use Adams's, 

 and also give two other constructions. But this is a 

 matter of detail. The proofs are neat and well suited to 

 beginners. A capital feature is the appending quite 

 elementary riders to the respective propositions, these 

 not being too difficult ; and in most cases, being true 

 riders on the propositions they follow, they will encourage 

 the young student to prosecute a study which becomes very 

 fascinating v\hen once the student gets a grasp of it. A 

 short chapter on orthogonal projection follows that on 

 the parabola, and is likely to be of use as showing the 

 intimate connection which exists between the circle and 

 the ellipse. A large collection of Cambridge problems, 

 duly labelled, closes the work. 



We have waited long for this quasi-authorized edition 

 of the Association's syllabus, " thereby hangs a tale," and 

 now it has reached us we are not disappointed. There 

 are very numerous figures, many of which are excellent, 

 but others are like Pharaoh's lean kine, " very ill- 

 favoured." 



Phoritmim tenax as a Fibrous Plant. Edited by Sir 

 James Hector, K.C.M G., M.D., F.R.S., &c. With 

 Plates. Second Edition. (Wellington, New Zealand : 

 By authority, George Uidsbury, Government Printer, 

 1889.) 



The original edition of this little hand-book appeared in 

 1872, since which period a great deal of consideration 

 has been given in this country to the further development 



of vegetable fibres generally, amongst which New Zealand 

 flax or hemp has had its share. The book has such a 

 varied amount of authentic information on the subject 

 with which it treats that the appearance of a new edition 

 is a distinct gain to those— and they are many — who are 

 occupied at present in the investigation of vegetable 

 fibres. 



The description of the Phorniiwn tenax., its habit and 

 rate of growth, cultivation, transplanting, and propaga- 

 tion, with an account of the native and European methods 

 of preparing the fibre, are all brought together here in a 

 compact form. The reports, prepared in New Zealand 

 by Messrs. Skey, Nottidge, and Hutton, together with 

 those of Profs. W. R. MacNab and A. H. Church, prepared 

 in this country, are also very valuable. These latter 

 appear in full in the new edition, and the former are in 

 some particulars more detailed. The book is, however, 

 almost a reprint of that which appeared in 1872, in some 

 cases even to the reproduction of errors ; thus on p. 2 

 of both the old and new editions the Raupo, Typha 

 atigtistifo/ia, is printed TypJms. 



The most interesting part, at the present time, of Sir 

 James Hector's new issue is, in consequence of its being 

 the newest matter, the preface, from which we learn that 

 during the last two years the demand for Phonnium fibre 

 has been steadily on the increase, and that one important 

 application is for the production of twine for use in 

 the harvesting machine, it having been found that as a 

 substitute for wire in reapers and binders no fibre is equal 

 to it. 



Revision of the British Actinice. By Prof A. C. Haddon. 

 Part I. (London : Williams and Norgate, 1889.) 



This revision of the British sea anemones by Prof. 

 Haddon, will be welcomed by all students of this in- 

 teresting group. We know a good deal already of our 

 native species, thanks to the writings of Sir J. Dalzell, 

 Dr. George Johnston, and P. H. Gosse ; and the last- 

 mentioned author, in his well-known " History of the 

 British Sea Anemones and Corals " (1858), succeeded, by 

 the aid of chromo-lithography, in giving very fair repre- 

 sentations in colours of the living forms. But the " Report 

 on the Actiniaria of the Challenger^'' by Richard Hertwig, 

 in which he sought by anatomical investigations to 

 establish a scientific classification of the group, opened 

 up a new standpoint for the study of these forms, of 

 which Prof. Haddon has most wisely and energetically 

 availed himself; and in this first part of his revision we 

 have a most excellent monograph of the Chondractiftitia, 

 and studies of several genera, which may be regarded as 

 more or less representing the various stages in the evolu- 

 tion of the typical hexamerous Actiniee. These latter 

 belong to the families Edwardsidcc and Halcampidce. 

 There is also a description of the remarkable Gonacti7iia 

 proli/era, Sars, some notes on Zoanthea; and on the 

 development of Actinise. 



Chitonactis ?nariofti, Paraphellia expansa, Edwardsia 

 tecta, and Halcampa arenarea, are described and figured 

 as new species. 



Seven plates accompany this memoir, of which the 

 first two, representing Chitonactis marioni, n. sp., Gephyra 

 dohrnii (von Koch), Actinange richardi (Marion), Para- 

 phellia expansa (g. et sp. nn.), Halcampa arenarea (n. sp ), 

 Choiidractinia digitata (Miiller), and an imdescribed 

 species of Sagartia, are very beautifully printed in colours, 

 being perhaps the most life-like illustrations of Actiniaria 

 as yet published in the Transactions of any of our learned 

 Societies. 



This memoir forms Part V. of the fourth volume of the 

 Royal Dublin Society's Transactions. 



Practical Iro7t- Founding. By the Author of " Pattern- 

 Making," &c. (London : Whittaker and Co., 1889.) 



This little volume is an attempt to give, in a condensed 

 form, an account of the principles and practice of iron- 



