26 FORESTRY [Bot. Absts., Vol. V. 



devotes considerable attention to a discussion of the status of French forests and the reforest- 

 ation movement during the nineteenth century, and quotes various legislative enactments 

 at length. .The paper contains much statistical information. — J. W. Bailey. 



182. De Vries. O. Over de bruikbaarheid van instrumenten als metrolac en latexometer 

 voor het bepalen van het rubbergehalte van de latex. [On the use of hydrometers (metrolac 

 and latexometer) to determine the rubber content of latex.] Arch. Rubbercult. Nederlandsch- 

 Indie 3: 207-221. 1919. — Very large differences may occur between the real rubber content of 

 Hevea latex as determined by actual coagulation and the figures obtained from the hydro- 

 metric specific gravity readings. The metrolac and latexometer are constructed for a special 

 case, perhaps an original latex of 37| per cent rubber content and 0.9775 specific gravity or 

 some other combination near there, when the specific gravity of the original serum varies 

 from 1.022. When such a latex is diluted with water the reading of the instrument is correct, 

 but for latices of other composition the rubber content cannot be determined by these instru- 

 ments. In general on the estates in Java the results obtained by hydrometric readings are 

 too low, usually giving values between 70 and 80 per cent of the real content. — W. E. Cake. 



183. De Vries, O. Verband tusschen het soortelijk gewicht van latex en serum en het 

 tubbergehalte van de latex. [The relation between the specific gravity of latex and serum and 

 the rubber content of latex.] Arch. Rubbercult. Nederlandsch-Indie 3: 183-206. 1919.— The 

 relation between the specific gravity of Hevea latex and its rubber content was determined 

 in the following five cases: (1) continued tapping after a period of rest, (2) light or heavy 

 tapping systems, (3) pollarding, which also acts as a "heavier stress," (4) periods of rest ami 

 shallow tapping, and (5) individual trees. In all cases the results are the same, showing that 

 the specific gravity is inversely proportional to the rubber content. The actual specific 

 gravity of the latex is determined by the proportion o the rubber and serum (i.e., the rubber 

 content of the latex) and only to a small extent by the specific gravity of the serum which re- 

 mains nearly constant. — W. E. Cake. 



184. De Vries, O., and W. Spoon. Variabiliieit van p'antage-rubber. [Variability in 

 plantation-rubber.] Arch. Rubbercult. Nederlandsch-Indie 3: 246-276. 1919. — Data from the 

 Central rubber station comparing the tensile strength, slope, rate of cure, and viscosity of 



moked sheet and crepe rubber for the years 1917 and 1918. The principal causes for devia- 

 tion and variability in properties are pointed out. — W. E. Cake. 



185. Essig, E. O. New hosts of oak-root fungus in Humboldt County. Monthly Bull. 

 Comm. Hortic. California 8: 79-80. 1919.— See Bot, Absts. 4, Entry 1170. 



186. F[oster], J. H. [Rev. of: Rankin, W. Howard. Manual of tree diseases. 398 p. 

 Macmillan Co.: New York, 1918.] Jour. Forest. 17: 321. 1919. 



187. Geete, Erik. Ur timmersaxens historia. [From the history of the timber "grab 

 hook."] Skogen 6: 23-25. 3 fig. 1919. 



1S8. Gellatly, F. M. Investigatory work needed: relation of commonwealth to states. 

 Australian Forest. Jour. 2: 137-139. 1919 — The more important benefits to be derived from 

 a forest products laboratory are discussed. Urgent need is voiced for research along the 

 following lines: (1) tests of pulping and paper-making qualities of indigenous woods and 

 materials, (2) distillation tests to determine the tar oil, gas, acid and other properties of 

 commercial value in indigenous woods, (3) investigation of the chemical and commercial 

 properties of gums, kinos, resins, and saps. — C. F. Korstian. 



189. Grinndal, Th. Tidig eller sen skogssadd? [Early or late forest sowing?] Skogen 

 6: 124-127. 1919. 



190. Gupta, B. L. New Indian species of forest importance. Indian Forester 45: 388- 

 392. 1919. — A continuation of previous work (Ibid. 43: 132. 1917). The present list includes 

 48 species recently described from India, bringing the total forest species up to 393. — E. N. 

 Munns. 



