1916] FORESTRY. 241 



Laboratory tests on the durability of American woods. — I, Flask tests on 

 conifers, C. J. Humphuey {Mycoloyia, 8 (1916), No. 2, pp. 80-92, pi. i).— The 

 author reports results of durability tests, extending over periods of 4, 6, and 

 12 montlis, of a number of American woods. 



Tlie tests were conducted in 2-liter Erlenmeyer flasks, plugged rather lightly 

 with absorbent cotton and capped with thin muslin which had been saturated 

 in a dilute solution of mercuric chlorid. The test blocks were placed in the 

 flask together with " culture blocks " and then inoculated with a culture of 

 Lentimis lepideus, grown on a bean pod. The " culture blocks " were irregular 

 hemlock blocks introduced as a medium to support a vigorous growth of the 

 fungus in order to secure a uniform and severe infection of the test blocks. 



The blocks were weighed before and after the test and the percentage loss 

 calculated from these data. 



Preservative treatment of timber, H. F. Weiss and C. H. Teesdale {Inter- 

 nat. Engin. Cong.. 1915, Sept. 20-25, Adv. Copy, pp. 45, figs. 3).— This paper, 

 presented at the International Engineering Congi-ess, San Francisco, in 1915, 

 comprises a general review of the results obtained in the United States in 

 preserving wood. A partial bibliography of the subject, covering American 

 practice, is appended. 



The properties of balsa wood (Ochroma lagopus), R. C. Cakpentee (Proc. 

 Amer. Soc. Civ. Fyiigin., 42 {.1916), No. 5, pp. 649-619, figs. 16).— Thin paper 

 shows the microscopical structure of balsa wood and also gives various tests 

 of its transverse and compressive strength. This wood has been used in the 

 past as a buoyancy product for life preservers and in connection with the 

 fenders of life boats and rafts. The various tests which were made of the 

 insulating properties of this wood indicate that it may prove of value as an 

 insulating material. 



Notes on the ancestry of the beech, E. W. Beery {Plant World, 19 {1916), 

 No. 3, pp. 68-77, figs. 2 ) . — A brief historical sketch of the beechea 



British Columbia Douglas fir (Pseudotsuga taxifolia) {Brit. Columbia 

 Govt.., Forest Branch Bui. 14 {1916), pp. 15, figs. 10).— An account of the 

 Douglas fir, with special reference to strength values under different tests as 

 compared vpith other species of structural timber. 



British Columbia western soft pine (Pinus ponderosa) {Brit. Columbia 

 Govt., Forest Branch Bui. 17 {1916), pp. 15, figs. 17). — An account of this species 

 with reference to its distribution and habit of growth, characteristics, and 

 uses of the wood. 



Influence of the intensity of thinnings on the yield of young regular 

 stands of spruce, E. Mer {Rev. Eaux et ForSts, 54 {1916), No. 2, pp. 45-53). — 

 In continuation of a previous report (E. S. R. 31, p. 444) the author gives the 

 results of thinning experiments started in 1899 in which young spruce stands 

 received thinnings of different intensities with special reference to the effect 

 of the thinnings on yield. The results in general indicate that both early and 

 relatively hea\T thinnings act advantageously on future yield. 



Manuring experiments on rubber, B. Bunting {Agr. Bui. Fed. Malay States, 

 4 {1916), No. 5, pp. 125-141). — This comprises a progress report on experiments 

 conducted to determine the influence of different manures on the yield of dry 

 rubber as measured by yield records for a period of 11 months. 



The differences thus far are too small to attempt comparative values on the 

 effect of the manures. The use of lime in connection with the different ele- 

 ments has resulted in increased yields, a complete fertilizer to which lime was 

 added giving considerable increase in yield. In addition to yield data records 

 are given of girth increase and cost of manures. 



