FOEESTRY. 739 



(1910), Xo. 7. })iK 256-276').— Notes are siven on some cnltiinil experiments of 

 I'ara rubber trees In the Singapore Botanic Gardens, consisting of data on the 

 yields of rubber from large and small trees, togetlier with tables showing the 

 increment of growtli during a 6-year period of a large number of trees as 

 influencetl by wide planting and by close planting. 



The difference in the quantity of latex between young and old trees of nearly 

 tlie same aggregate girth is uot very large, although variable. The ratio of 

 rubber to the volume of latex between young and old trees is considerably higher 

 in old trees. The necessity of wide planting as the most important factor in 

 the annual increment of growth of rubber trees is pointed out. The increment 

 of growth of Para trees is variable according to situation, soil, and humidity, 

 and the ratio of increment also varies according to the age of the tree. In 

 general it is stated that the average increment should not be less than 2 in. 

 per year between the third and thirtietli years. 



Notes on the experiments of coagulating and curing rubber, H. N. Ridley 

 (Afff. Bill, iitiuits and Fed. Malay States, 9 {1910), No. 7, pp. 277-28// ) .—Several 

 experiments were made at the Singapore Botanic Gardens in curing latex by 

 smolving as is done in Brazil, the aim being to test whether the coagulated 

 iatex from plantation trees would be improved or deteriorated by such process. 

 Samples of smoked rubber were submitted to the Imperial Institute and to 

 commercial works for a])praisement. 



The general results indicate that tlie rubber prepared by smoking is only a 

 little below fine, hard cured Para, and the author is of the oi)inion that the 

 Iveeping qualities of the plantation rubbers in the crude state will be improved 

 by creosoting or smoking. The difference in the physical texture and appearance 

 of rubber from young or old trees coagulated with such reagents as acetic acid 

 is scarcely perceptible, whereas under tlie smolving process the superior strength 

 and elasticity of the resulting rubber from old trees is manifest. 



Bleeding Hevea rubber trees by the Northway system, M. T. Petch 

 (Jour. Af/r. Trop.. 10 {1910), Xo. 109, pp. 193-196, pgs. /,) .—The^orthwny system 

 of tapping trees, wliich consists of the use of a pricker instead of a Ivuife, is 

 described in detail and the objections of a physiological and practical nature 

 accompanying the use of the pricker are discussed. 



The general conclusion Is reached that the incision metliod of tapping, as 

 with the pricker, has after wide experimenting proved inferior to the excision 

 method of tapping, as with different forms of tapping knives. Not only were 

 the returns inferior wliere the pricker was used but the cost of harvesting was 

 inci-eased and more damage done to the trees. Moreover, the pricker is only 

 adapted for use on young trees, the quantity of latex from which is too small 

 to justify their tai)ping. 



Annual report on the literature and important happenings in the realm 

 of scientific forestry, forest zoology, agricultural chemistry, meteorology, 

 and forest botany for the year 1909, II. ^YEBEB {AUg. Foist u. Jagd '/Ay., 

 1910, Hill)., pp. 102). — As in previous years (E. S. R., 21, p. 445), this supple- 

 ment contains abstracts of tlie important literature on the various phases of for- 

 estry, together with notes on important occurrences in the forest world for the 

 year 1909. The topics included are silviculture, utilization, management, valu- 

 ation and statics, tlie theory of forest mensur.ition and yields, administration, 

 history, jiolicy, statistics, news of forest unions and hunting clubs, zoology, 

 botany, and soil physics. 



