126 



NA rURE 



[December 9, 1897 



OUR BOOK SHELF. 



Bau und Leben unserer Waldbdume. Von Dr. M. 



Biisgen, Professor an der grossherzoglich sachsischen 

 ■ Forstlehranstalt in Eisenach. Pp. viii + 230, mit 100 



Abbildungen. (Jena: Verlag von Gustav Fischer, 1897.) 

 This comprehensive volume on forest botany, which 

 is essentially on the same lines as the well-known 

 text-books of Dobmer-Nobbe, Hartig, and Schwarz, gives 

 an interesting account of the structure and physiology 

 of forest trees. The introductory chapters are devoted 

 to a general external survey of the tree, note being made 

 of the various forms of buds and shoots, while the in- 

 fluence of their position and development on the habit 

 of trees is clearly indicated. An interesting subject is 

 touched upon in the annual and periodic rate of height- 

 growth, and reference is made to the relationship that 

 exists between the rapidity of growth in youth and the 

 light-requirements of trees. With hardly an exception 

 trees that are intolerant of shading grow with great 

 rapidity when young (larch, birch, &c.), and are thus 

 enabled to keep their crowns well above the level of 

 those of competing species. Slow-growing species, on 

 the other hand, are not prejudically affected by moderate 

 shading (silver fir, beech, &c.). Were they otherwise 

 they could hardly have survived in the mixed primaeval 

 forest, where the struggle for existence proceeded with- 

 out interference from the woodman's a.xe. 



An important section of the book deals with the 

 annual wood-ring, the characteristics of which are so 

 useful in aiding in the identification and in explaining 

 the properties of timber. Although our knowledge of 

 the causes that lead to modifications in the annual ring 

 of trees has been much advanced of recent years, the^e 

 are still many interesting problems awaiting solution, as, 

 for instance, in the matter of eccentric growth. The 

 explanations that are usually offered can hardly be said 

 to be sufficient to account for the constant eccentricity 

 that occurs on sections of wood taken from roots and 

 branches, as well as from stems that have grown upon 

 a hillside. And even after all that has been written by 

 Sachs, de Vries, Krabbe, Hartig, Strassburger, and 

 others, who will confidently say whether pressure, nutri- 

 tion, physical exhaustion of the cambium, water, or 

 heredity is the true cause of the difference that exists 

 in the structure of wood formed early and late in the 

 growing season ? 



After discussing the formation of duramen and the 

 properties of timber — where, by the way, one misses any 

 reference to the latest work of Roth in America and of 

 Schwappach in Prussia — the author proceeds to an ex- 

 amination of the leaf and root. As was to be expected, 

 a good deal is said regarding the many theories that 

 have from time to time been advanced to account for 

 the ascent of water in trees — so ably summarised up to 

 date by Marshall Ward in his book on timber — and 

 while greatest prominence is given to Strassburger's 

 experiments, the work of Dixon and Joly receives ap- 

 preciative recognition. A chapter on fruits, seeds, and 

 seedlings completes a volume which, while designed 

 chiefly for foresters, cannot fail to be of use to a larger 

 public, and especially to students of botany. 



William Somerville. 



Physiography for Advanced Students. By A. T. Sim- 

 mons, B.Sc. Pp. viii 4- 483. (London : Macmillan 

 and Co., Ltd., 1897.) 

 This book is a supplement to " Physiography for 

 Beginners " by the same author, and for those who have 

 mastered the earlier work it will furnish an excellent con- 

 tinuation course. Matter, energy, the air, the sea, and 

 kindred subjects occupy more than half the volume, 

 while the description of the different members of " the 

 universe " and of the various natural laws relating to 

 them, occupies the remainder. 



NO. 1467, VOL. 57] 



Both terrestrial and celestial subjects are admirably 

 dealt with, the explanations being clear and to the point, 

 and the selection of illustrations, which number 218, 

 leaves nothing to be desired. The experimental method 

 so successfully adopted in the previous book has been 

 adhered to as far as possible, though there is naturally 

 less scope than before for this treatment. Another 

 notable and praiseworthy feature is the large number 

 of references to books and Proceedings of societies deal- 

 ing with special branches of the subject, and it is 

 much to be desired that advanced students should 

 acquire the habit of utilising information of this kind. 



At the end of each chapter is a series of test ques- 

 tions, which will doubtless be greatly appreciated by 

 teachers. There is also a summary of the chief points 

 of each chapter, which will be valuable if not misused ; 

 but there is possibly some danger of the less serious 

 students confining their studies to these condensed 

 statements. 



We believe that the book will admirably supply the 

 need which must have been felt by teachers and students 

 under the new conditions created by the revised syllabus. 

 In conjunction with the volume to which it is a supple- 

 ment, it will also provide the general reader with a com- 

 prehensive view of the earth and its relation to other 

 bodies in space. 

 Chemistry for Photographers. By C. F. Townsend, 



F.C.S. Pp. xviii -t- 158. (London : Dawbarn and 



Ward, Ltd., 1897.) 

 Great is the number of those who practise the art of 

 photography at the present day, but how many of these 

 are acquainted with the chemical reasons underlying the 

 numerous manipulations which are performed ? Every 

 photographer, it does not matter how much or how little 

 he employs his camera, should make himself familiar 

 with, at any rate, the chief rudiments of this science, 

 even if he does not wish to enter more deeply into 

 details. 



The book which we have before us gives the reader a 

 concise and clear insight into the various chemical ques- 

 tions which come into the sphere of photography. Th e 

 author has carefully drawn attention to the fact, that by 

 good judgment, and by paying heed to the actions of 

 various chemicals employed, the photographic plate can 

 be made to give results far better than when such know- 

 ledge is lacking. 



Not only is the chemistry of the photographic image, 

 developers, reversal, intensification and reduction, print- 

 ing, &c., clearly explained, but useful information is col- 

 lected, bearing on impurities, recovery of residues, cellu- 

 lose, resins, varnishes, &c. Curiously enough, no mention 

 is made concerning the pros and cons of mounting solu- 

 tions, an important question for those who wish their 

 prints to last more than a year or two. Perhaps this 

 subject will receive attention in a future edition. 



The book should be read by all who wish to gain an 

 insight into the chemical side of photography. 

 My Fourth Tour in Western Australia. By Albert 



F. Calvert, F.R.G.S. Pp. xxvii -f 359. (London : 



William Heinemann, 1897.) 

 Mr. Albert Calvert has written much upon Western 

 Australia, and has been generous in publishing his views 

 and convictions as to the mineral resources of that Colony. 

 He now informs his readers that the object of previous 

 works was to advance the interests of the Colony, whereas 

 in the present volume the subject is treated " entirely from 

 a personal standpoint." Open confession is proverbially 

 good for the soul, and by declaring that the book con- 

 tains a narrative of personal impressions, intended to 

 interest and amuse the public, Mr. Calvert leaves no 

 room for doubt as to the purpose of his new publication. In 

 keeping with this object, a number of illustrations of purely 

 personal matters are included in the volume. 



