58 Forestry Quarterly. 



of the sprvice forest whose northern limit is thus defined are the 

 White and Black Spruce, whose range is co-extensive with the 

 forest limits, the Canoe Birch, Tamarack, Aspen, and Balsam 

 Poplar, Banksian Pine and Balsam Fir are common in the 

 southern part of the belt, terminating from south to north about 

 in the order given. With these are associated generally in the 

 form of undergrowth, a variety of shrubs. The tree limit on the 

 western mountains in latitude 56 is at about 4000 feet. The 

 head of the Mackenzie delta is marked by islands well wooded 

 with spruce and Balsam Poplar. Lower down these trees give way 

 to willows which continue to sea. The interesting observation 

 is made that the trees of the swamp in their more northern fields 

 seek the dry land. 



The life zones included in the region comprise parts of three 

 subdivisions — the Arctic, Hudsonian, and Canadian Zones. The 

 boundaries of these zones are shown in a very useful map in 

 considerable detail. Each zone is summarily described in a clear 

 and comprehensive manner. B. E. F. 



India-Rubber and its Manufacture. With Chapters on Gutta 

 Percha and Balata. By Hubert L. Terry, 294 pp., 18 illustra- 

 tions. D. Van Nostrand Company, New York, 1907. (Price, 

 $2.00) . 



India rubber has become an almost indispensable commodity, 

 and this circumstance has stimulated the interest of the public in 

 its natural history and its manufacture. This volume is not a 

 handbook for those engaged in the rubber trade. Its purpose is 

 to supply to the general and the critical reader the latest in- 

 formation relating to the whole subject of India rubber. Mr. 

 Terry has admirably carried out his design, and the fact that the 

 story of rubber and its uses is of unusual interest has enhanced 

 the readable quality of the book. 



The author tells of the discovery of India rubber's characteris- 

 tics and usefulness, describes its production, explains its chemical 

 and physical properties, and deals with vulcanization and other 

 processes. The chapter on India rubber plantations shows how 

 widely and successfully American rubber plants, especially Para, 

 and Castilloa have been introduced into Asia. There are chapters 

 on "India rubber substitutes", "reclaimed rubber", "the washing 



