FORESTRY. 743 



The Franquette walnut, M. McDonald {Pacific Rural Pvcks, 13 {1901), No. 

 7. pp. 100). — The author discusses the value of the Franquette walnut as com- 

 pared with other French varieties for planting in Oregon. 



Figures are given showing the increase in yield of a Franquette grove at 

 Santa Rosa. California, from the time the trees were 3 years old in 1001 until 

 they wore S years old in V.)0(\. DiUMng this period the total yield increased 

 frou) S2 ll)s. to 24..'>14 Ihs., and tlie output i)racticnlly doubled for each year after 



The chilte tree, Costantin and (Jai.lauu {liei\ 0('n. Bot., 18 {1906), No. 

 21.'i, pp. 38.j-.}91, fiijs. 2). — An account, including the method of exploitation and 

 an illustrated botanical description, is given of the chilte tree of Mexico, for 

 which the authors propose the name of Jatropha trpi(]iien.'^is. The seeds are 

 used as food in Mexico and the gum is said to have taken the place of chicle 

 (R. S. I!.. 17. ]). 257) in the manufacture of American chewing gum. 



The culture of Ficus elastica {Bui. Off. Gouvt. G6n. Algcrie, 1901, Sup. 1. 

 pp. IS). — This work treats more particularly of the species of Ficus adapted 

 for the iirodnction <tf rubber. The characteristics which differentiate the Ficii>i 

 elastica from /•'. inafmolioidcs are pointed out. 



The manurial requirements of rubber trees {Trap. Life, 3 {1901), No. 1, pp. 

 3-'), fif/f>. -'/). — I'oiiular directions are given for the use of commercial fertilizei's 

 in the culture of rubber trees. 



Wliat I saw in the Tropics, II. C. Pearson {New York: India RiiJiher Pah. 

 Co., 190(). pp. 296, fifffi. 289). — The author relates his personal experiences and 

 adventures during visits to Ceylon, the Federated Malay States, Mexico. Nica- 

 ragua, Costa Rica, Republic of Panama, Colombia, Jamaica, and Hawaii. Con- 

 siderable information concerning the present status of the rubber industry and 

 the various species and varieties under cultivation in these countries is given. 



Besinous secretions and resin ducts, A. Tschirch {Die Harze and die 

 Harzhrhdltcr. Lrip.^ir: Bonitragcr Bros., 1906, vols. 1, pp. XXII + 1902; 2. 

 pp. 1093-1268. fi(/s. lO.'i). — Volume 1 is a chemical study of resinous secretions 

 and their products. Volume 2 consists of a botanical study of the ducts which 

 contain these resinous secretions. Under resinous secretions the author 

 includes the saps of coniferous, euphorbias, and all rubber-producing trees. 

 The treatise is based on extensive researches of the author and several collabo- 

 rators, together with information secured from many scientific works. 



Effect of moisture upon the strength and stiffness of wood, H. D. Tiemann 

 (f. aS'. Dept. Affr., Forest Serv. Bui. 70, pp. l',',, pis. //. figs. 25). — This bulletin 

 is a report of a series of tests conducted by the Forest Service in conjunction 

 with the Yale Forest School under the direct supervision of the author. All 

 of the important features of the work are discussed in detail and the results 

 are set forth in numerous tables, figures, jilotted curves, and plates. 



Besides the main tests, which include the important phases of compression 

 parallel to grain, bending, shearing, and compression at right angles to grain, 

 special tests were made to determine other closely related problems such as the 

 fiber-saturation i)oint, the effect of temperature upon this point, the effect of 

 steaming and boiling, of time of soaking, and of casehardening, and the determi- 

 nation of volatile oils. In all, the report includes over 1,600 mechanical tests 

 and nearly three times as many moisture determinations were made. 



Three species of wood were studied and compared. Ijongleaf pine {Pi mis 

 palustris) and red spnice {Picea ruhens) were used as repi-esentative conifer- 

 ous woods, and the chestnut {Castaiiea deufata) as representative of the ring- 

 porous woods. The test specimens were made of the size considered the most 

 satisfactory for experimental purposes, viz, of 2 by 2 in. stuff of different 

 lengths. The results apply especially to the smaller forms of hard and soft 



