BOOK REVIEWS* 



117 



estimated at about 32,000,000 lb., or 5 ounces a head of the popula- 

 tion. A large home market, therefore, already exists, and in view of 

 the food value of the date this could probably be greatly increased 

 with advantage to the consumers were it possible to produce clean 

 dates of good quality and appearance in the country. 



The book gives full details regarding the soil and climatic require- 

 ments of the date-palm, and the importance of propagating suitable 

 varieties by means of offshoots rather than by seeds is emphasized. 

 Particulars are also given as to the artificial pollination of the flowers, 

 the methods of handHng and ripening the crop, the pests and diseases 

 to which the trees are liable, and of the cost of forming a plantation 

 and the probable profits to be derived therefrom. A descriptive Ust of 

 varieties is also given. Intending planters in the States, for whom the 

 book is written, will find in it much useful information, and general 

 readers will also find it interesting, particularly those chapters on the 

 food value of the date contributed by Charles L. Bennett, M.D., and 

 the Arab uses of the date. The book contains some excellent photo- 

 graphs and is furnished with a full index. 



" Rubber and Rubber Planting." By R. H. Lock, Sc.D. 8vo., 

 xi -f 245 pp., with 10 full-page illustrations and 22 figures in the text. 

 (University Press, Cambridge, 1913.) 5s. net. 



Owing to the heavy fall in the price of rubber during the last two 

 years, the interest taken in this product by the general public has 

 somewhat waned ; nevertheless there is a sustained increase in the 

 number of books treating of this subject in some one or other of its 

 many aspects. In this handbook Dr. Lock attempts to cover a rather 

 wide field, in that he treats of both wild and cultivated rubber and also 

 of the chemistry of rubber and the manufacture of rubber goods. 



By far the greater part of the book is devoted to plantation Para 

 rubber {Hevea hrasiliensis) , which is now being produced in large and 

 increasing quantities in the East, especially in Ceylon and the Fede- 

 rated Malay States. Dr. Lock was formerly Assistant Director of the 

 Botanic Gardens in Ceylon, and in that capacity conducted many 

 experiments in connexion with the rubber industry, particularly with 

 regard to tapping the Hevea tree. The results of these experiments 

 are set forth in the handbook, together with an interesting account of 

 the physiology of latex production and the chemical composition 

 of latex. Other chapters treat of the practical work in connexion 

 with planting operations, the collection of the latex, and the preparation 

 therefrom of rubber for export. The manufacture and chemistry of 

 rubber are briefly dealt with in the concluding chapters. 



Although there is little that is new in the handbook, the information 

 is accurate and is presented in a convenient and readable form. 



The illustrations comprise reproductions of photographs and figures 

 in the text ; the latter, representing different rubber-producing species, 

 were drawn by Mr. L. Denton Sayers, and form a valuable feature 

 of the book. 



