Oct. ici: " 



KNOWLEDGE & SCIENTIFIC NEWS. 



249 



British Mosses. — The doclared object of the first edition of 

 " The Student's H.indbook of British Mosses." by M. N. Dixon 

 and H. G. Jameson (Snmfield, I'astbounie : Wholdon. London), 

 was to provide a practical handl)Ool< to the mosses of these 

 islands in snch a form as to be accessible to students: and we 

 are pleased indeed to see that after eif;ht years this modestly- 

 stated ambition has been rewarded by the call for a second 

 edition. It is a reward far from immodest for a book which is 

 in the highest degree useful, not to say indispensable, to the 

 student : and which is compiled with a wealth of care such as 

 perhaps would be taken by no one but the painstaking race of 

 botanists for whom the consciousness that genius is the 

 cap.acity for taking small pains must be a frequent, .md. we 

 hope, a not altogether barren consolation. Since the pulilici- 

 tion of the first edition sonic thirty species or subspecies have 

 been added, tSgcther with ,a corresponding number of varieties 

 of greater or less value. Recent research has added more 

 precise knowledge of older varieties and has sometimes made 

 changes in nomenclature necessary. It has not been possible 

 to interpolate these additions to knowledge bodily in the 

 volume without some alteration in its arrangement : but the 

 changes that have been made in a classification, with which 

 the authors had every reason to be satisfied, have been made 

 with extreme care. The authors believe that such as are m.uU- 

 will be found to be improvements, a belief which criticism 

 may endorse. 



Electro Chemistrj'. — To the series of text books on Physical 

 Chemistry ^Longmans. Green) to which Sir William Ramsay 

 wrote the general introduction, Dr. Lehfeldt has contributed 

 the volume on '• Electro Chemistry." This volume deals with 

 the theoretical side of the subject only ; the application of 

 the theory to the practical consideration of primary and 

 secondary cells, to electrolysis, and to the solution of chemical 

 problems is to follow. The relation between quantity of 

 electricity and quantity of chemical action is elucidated in a 

 chapter ranging from the consideration of Faraday's laws of 

 electrolytic deposition to the Arrhenius theory of dissociation 

 and its corollaries in respect of the conductivity of mixtures. 

 The relation between electric intensity and the intensity of 

 chemical action follows as a sequence to the first, and con- 

 siders the theories of concentration, polarisation, &c., under 

 the comprehensive heading of the theory of chemi-electro- 

 motive force. \ chapter which the preface obligingly states 

 can be missed by those who are not interested in pure 

 chemistry, but which will probably not be missed by anvone 

 who desires to keep in touch with the modern theories of 

 chemical solution, is interpolated by Mr. C. S. Moore, on the 

 relation of Chemical Constitution to Conductivity. The con- 

 centration of information in the text book is not its least 

 noticeable feature. 



Kinetic Theory. — In "Applications of the Kinetic Theory" 

 (Macmillan), Professor W. P. Hoynton cndea\ours to present 

 the probable or possible relations to one another of the facts 

 of electrolysis, of osmotic pressure, and the general pheno- 

 mena of dissociation and solution, as seen by the light of the 

 kinetic theory. In successive chapters, the kinetic aspect of 

 ideal gases, of gases with molecules that have dimensions, of 

 the conduction of electricity and heat; of vaporisation ; of the 

 behaviour of molecules within a liquid: of solutions; of disso- 

 ciation and condensation, are dealt with. The volume is one 

 of great suggcstiveness to advanced students of physical 

 chemistry, and though the author disclaims any originality of 

 treatment, he displaysjudicial and selective powers of analysis 

 and arrangement of the highest order. 



Visceral Inflainmations. — It has been said that there is a 

 fashion in diseases; and in this casual observation there is the 

 grain of truth that increased knowledge implies more precise 

 classification of diseases ascribed loosely to causes and symp- 

 toms which may be merely incidental. Thus, as we are re- 

 minded by the papers and addresses which Dr. David B. Lees 

 has collected in "The Treatment of Some Acute Visceral 

 Inflammations" (John Murray), the knowledge which in the 

 last twenty years has been gained of pneumonia, appendicitis, 

 . rheumatism, and the acute inflammations of the heart and 

 kidneys, has resulted in an apparent increase of the number 

 of cases classified under these heads. As an instance of what 

 we mean, we may (juote the cases of appendicitis, which for 

 generations past have been ascribed to varying causes, many 



of them totally unfounded, but which are now grouped under 

 the primary cause of an acute local iufl.-unmation. Similarly, 

 the increase of knowledge in bacteriology has trausfornied 

 the view taken of diseases such as pniMuuouia, and is throw- 

 ing new light on many rheumatic allectious. But the advanc(^ 

 of treatment of these diseases has not kept pace with the 

 advance of knowledge of their causes; and the treatises of 

 those who, like Dr. Lees, have euqiloyed sixteen years of hos- 

 pital work in the practical consideration of them, have the 

 highest value, and are of the highest interest inside and out- 

 side the medical profession alike. It is, of course, as a text- 

 book of medical treatment that such a volumi- is compiled; 

 but we h;ive no hesitation in according it notice iu columns 

 which are chiefly intended for the review of general scientific 

 literature. Its chief contents are lectures on carditis, 

 pneumonia, empyema, pleurisy, appendicitis, and nephritis, 

 with other papers on he;irt affections, their connection with 

 rheum.itism, especially in children ; and some of the heart 

 symptoms which follow influenza. 



Common Animals. — Among the many good points of " The 

 Natural History of some Common Animals," by Oswald H. 

 Latter, M.A. (Cambridge L'niversity Press), is the extreiui'ly 

 natural and logical way in which it teaches elementary zoology. 

 Mr. Latter would divorce from elementary teaching of this 

 subject the notion that structure must occupy the first, and 

 almost the only, place in any method of study; and would 

 impress on the minds of tlie instructed the necessity for 

 learning function as well. In this way, .as we believe, lies the 

 best chance and opportunity of impressing on the mind of tlie 

 young student a liking for the subject; and in impressing on 

 his memory the relatively important details. Mr. Latter has 

 thus chosen a few animal types as the best to suit his purpose, 

 and has taught something about everything conceruiug them. 

 The types selected are the Earthworm, Leech, Crayfish, Cock- 

 roach, Dragonfly, Wasp, Fresh-water Mussel, Snail, Slug, 

 Frog, To.'id and Newt, and some of the common internal para- 

 sites of domestic animals, and of these he has given a full 

 biological and bionouiical n.arrative. Of its kind this book is 

 one of the best that has yet been written ; its manner and 

 matter are alike excellent. 



Practical Geometry. — The " Practical Geometry for Begin- 

 ners " (Macmillan and Co.), which has been compiled by 

 W. L. Neve Foster and F. W. Dobbs, is based on the sound 

 logic that the best way of preparing the youthful mind for 

 theory is to suggest to it concrete values of lines, angles, 

 perpendiculars, radii, and all the other furniture of geometry. 

 Thus the book teaches geometry with the box of matliematlcal 

 instruments, and a triangle no longer rem;uns a symbol A BC 

 or D E !■", but is something tangible, measureable, comparable. 

 This is but a hint of the method which eventually [)roceeds to 

 the practical verification of theorems and laws, and which 

 may be couunendcd as practically useful and educationally 

 interesting. ^ 



Technical Thermometry. — The Cambridge Scientific Instru- 

 ment t'ompauy sends us a copy of their list on "Technical 

 Thermometry," together with an intimation that the lists can 

 be obtained from them, on application, by readers of " Knovv- 

 I.ICDGK." The list is a summary of the latest methods and 

 appliances in electric thermometry ; and, apart from its use to 

 students, it is of instructional value in defining the practical 

 applications of electrical thermometers in annealing furnaces, 

 in boilers and superheaters, and in explosive sheds. The 

 thermometer, and, above all, the exactly and inst.intancously 

 recording thermometer, has become, in recent years, of the 

 utmost importance to chemical works, to the brewing industry, 

 and to engineers and manufacturers in increasing numbers. 

 The catalogue before us is a summary in brief of the instru- 

 ment's use and practice. 



The new catalogue of Messrs. Isenthal and Co.'s Electric 

 Heating Apparatus forms a not iminteresting record of the 

 various uses to which any householder can turn the electric 

 current supplied to him from the mains. l'~or readers of 

 " Ksowi.KDGH " the list is chiefly of service in detailing the 

 uses to which electric heating apparatus can be put in the 

 laboratory or the hospital, liut the limits to the purposes to 

 which electricity can be applied in the dwelling-house, the 

 kitchen, the workshop, and the factory are becoming enlarged 

 every day. 



