NA TURE 



241 



THURSDAY, AUGUST 26, 1909. 



TREE-FLORA OF JAVA. 

 Mikrographie des Holzcs der auf Java vorkomntciuicn 

 Baumarten. By Dr. J. W. Moll and H. H. Jnns- 

 sonius. Erste Lieferung (1906), pp. 368; and 

 Zweite Lieferung (1908), pp. 369-568+160. (Leyden : 

 E. J. Brill.) Price 6 marks each. 



THIS work, like the earlier tree-flora of Java, was 

 undertaken at the suggestion of Prof. I\I. Treub, 

 director of the Botanic Garden at Buitenzorg. It will 

 be convenient to begin by making a short reference to 

 this earlier publication. 



In the year 1888 Dr. S. H. Koorders began to collect 

 material for a tree-flora of Java. The work con- 

 nected with the compilation of this flora was carried 

 out in a most careful and methodical manner. More 

 than four thousand trees, many of which were in the 

 primeval forest, were marked, and a special system 

 of numbering the trees, and of indexes and maps, was 

 instituted, so that each tree could be easily Tound 

 again, and the rate of growth, leaf fall, &c., could 

 be studied. In the course of naming and studying 

 the plants for the tree-flora of Java (" Flora arborea 

 Javanica," by S. H. Koorders and Th. Valeton), a 

 collection of fifteen thousand specimens was made to 

 illustrate the species dealt with in the flora. 



This collection included a series of wood-specimens, 

 which were sent in 1904 from Buitenzorg to the Uni- 

 versity of Groningen for microscopic examination and 

 description, and this work has been carried out, under 

 the direction of Prof. J. W. Moll, by Herr H. H. 

 Janssonius. The results appear in the present work, 

 which may therefore be described as a counterpart to 

 Koorders and Valeton 's flora in the province of the 

 anatomy of the wood. Hence a most important asset 

 in the value of the work lies in the fact that there is 

 no uncertainty as to the origin of the specimens. 

 They have all been obtained from trees which have 

 been carefully studied and determined by an expert, 

 and, moreover, herbarium material froin the same 

 trees is to be found in the herbaria at Buitenzorg, 

 Leyden, Berlin, &c. 



In this work the authors have adopted a very 

 orderly arrangement of the information. Under each 

 species there are five principal headings, beneath which 

 are given the literature, information on the materi;d, 

 the preparations made, the reagents used, and, lastly, 

 under the name of micrography, a description of the 

 structure of the wood. The section on micrography is 

 generally subdivided into one on topography, dealing 

 chiefly with the distribution of the tissues and elements 

 as seen in transverse section, and another giving de- 

 scriptions of the individual elem.ents, based on a study 

 of radial, tangential, and transverse sections, some- 

 times supplemented by macerated preparations. A 

 separate paragraph is devoted to each kind of element, 

 and gives full details of measurements, pitting, con- 

 tents, &c. The section on topographv is elucidated, 

 in cases where this is advisable, by means of a dia- 

 grammatic figure showing the distribution of the 

 vessels, w'ood-parenchyma, medullary rays, &c., in a 

 NO. 2078, VOL. 81] 



portion of a transverse section. When several species 

 of a genus are found to differ only slightly in the 

 structure of the wood, one of them is fully described, 

 and the description of the others is shortened by com- 

 parative treatment. Under each family, except where 

 only one species is dealt with, there is a description 

 of the structure of the wood, founded on that of the 

 different species described, and an analytical key for 

 distinguishing the species, so far as this is possible by 

 means of the wood, is added. 



Part i. contains, first (pp. 5-62), general informa- 

 tion, including the history of the material and an ex- 

 position of the method adopted in presenting the in- 

 formation in the succeeding pages. The remainder of 

 part i. (pp. 63-368) is occupied by the description of 

 the microscopic structure of the wood in species from 

 Dilleniaceae to Dipterocarpaceae. Part ii. (pp. 

 369-547) continues the same from Dipterocarpacese to 

 Tiliacese, followed by the index and contents of vol. i., 

 after which pp. 1-160 form a first instalment of 

 vol. ii., extending from Geraniaceae to Meliaceae. The 

 last page of part ii. reaches species No. 230, twenty- 

 one families having been dealt with up to this point. 



The foregoing description of this work will serve to 

 indicate its value, which lies in the authentic nature 

 of the specimens, the large number of species and 

 families dealt with, the completeness of the descrip- 

 tion of the microscopic structure, and, lastly, the strict 

 uniformity of treatment adhered to by the authors. 



This book will be an important aid in the deter- 

 mination of wood-specimens, and the authors are to 

 be congratulated on the efficient way in which they 

 are carrying out a difficult and laborious task. 



L. A. B. 



TWO AMERICAN MATHEMATICAL BOOKS. 

 (i) Plane and Spherical Trigonometry and Four-place 

 Tables of Logarithms. By Dr. Wm. A. Granville. 

 Pp. xii-l-264-1-38. (London : Ginn and Co., n.d.) 

 Price 5x. 6d. 

 (2) A Course of Mathematics for Students of Engin- 

 eering and .Applied Science. By Fredk. S. Woods 

 and Fredk. H. Bailey. Vol. II. Pp. xii-t-410. 

 (London : Ginn and Co., n.d.) Price los. 6d. 

 (i) "T^HE type and diagrams in this book are models 

 -L of elegance and excellence ; evidently no 

 pains have been spared in making both as clear and 

 perfect as possible, and the logarithm tables at the 

 end of the book add greatly to its completeness. One 

 useful feature in them is the table of circular functions 

 with the angles expressed in degrees and decimals of 

 a degree, in addition to the usual table in degrees and 

 minutes. The author also supplies a neat celluloid 

 combined protractor and scale in a pocket attached 

 to the cover. 



In the plane trigonometry the author introduces the 

 student to practical examples in connection with right 

 triangles in the first chapter, but does not proceed to 

 the solution of oblique triangles until chapter vii., after 

 discussion of functions of the generalised angle, the 

 addition theorems, inverse notation, and trigonometric 

 equations, but to a certain extent teachers can choose 

 their own order in taking these chapters. 



K 



