FORESTRY. 951 



woods used in tlio manufacture of vehicles and imiJlements and of tlie woods 

 whicli nii.i;lit he suhstitnted for tliose at present used. The various Idnds of 

 wood used are considered rehitive to their use for light vehicles, heavy veliicles, 

 and for inii»lenients. Tahulated data with numerous figures relative to labora- 

 tory tests made with buggy spokes and shafts, wagon axles, and wagon and 

 cultivator poles of different species of wood are given and discussed. 



While the tests in some cases are considered only suggestive, owing to the 

 small number of samples tested, some general conclusions are drawn relative to 

 the i)resent methods of grading, together with suggestions for their improve- 

 ment. 



Turpentine and rosin (Bur. of the Census [U. 8.] Bui. 85, pp. 43-51). — A 

 comparative statistical discussion of the manufacture of turpentine and rosin, 

 as reported from the census of 1905 and at previous censuses, together with a 

 discussion rehitive to the immediate future of the industry. 



Wood paving in the United States, C. L. Hill (U. S. Dept. Agr., Forest 

 Serv. Circ. IJfl, pp. 2Jt, figs. 3). — With the view of securing some cheaper and 

 more abundant varieties of wood than longleaf pine for use as paving blocks, 

 the Forest Service gathered data upon creosoted block pavements in several 

 cities in the United States where such pavements are used, and at those 

 creosoting plants which treat wood paving blocks. 



In the present circular the data thus secured and the conclusions drawn 

 from them, together with a description of an experimental pavement laid in the 

 city of Minneapolis, are given. The various phases discussed include the 

 progress of wood paving, the qualities of creosoted wood pavement as compared 

 with other forms of pavement, the cost, service, durability, traction resistance 

 and fi-eedom from slipperiness ©f wood pavements, problems in wood paving 

 relative to knowledge of the wood, use of laboratory tests, creosoting, and a 

 discussion of the points involved in laying pavements. 



The woods "used in the experimental pavement at Minneapolis were longleaf 

 I line, Norway pine, tamarack, Douglas fir, western larch, white birch, and hem- 

 lock. Traffic records are to be taken by the city authorities at regular intervals. 

 The final results will not be obtained for several years. With reference to the 

 use of Norway pine for paving blocks, it is stated that after 5 years' service 

 there is no discernible difference in wear between the heart and sap portions of 

 unseparated blocks. Norway pine appears to be wearing as well as longleaf 

 pine. 



The influence of fresh and salt waters on the utilitarian properties of 

 the principal species of wood, G. Janka and N. L. R. von Liburnau (Mitt. 

 Forstl. Versuctt.siD. Osterr., 1907, No. 33, pp. ^'111+115, figs. 16). — The investi- 

 gations included a cooperative study of the influence of fresh and salt water on 

 both the mechanical and technical properties of wood, and upon their chemical 

 analyses. The tests included observations on shrinking, swelling, and checking, 

 and as to the effect upon durability and strength. The results are set forth in 

 numerous tables and further discussed. 



The general conclusions are reached that the soaking of wood in fresh water, 

 such as occurs in the process of I'afting the logs and where wood becomes fre- 

 (luently wet from showers, and in similar ways, exerts a favorable influence on 

 the wood by decreasing the hygroscopicity and thereby decreasing the shrinking 

 and swelling, as well as lessening the danger of cracking to some extent. A 

 favorable influence is also exerted on the durability of the wood, although the 

 strength is lessened to a slight degree. Soaking in salt water appears to lessen 

 the shrinking over that of unsoaked wood, but with the increasetl higher salt 

 content the hygroscopicity is increased, which causes a greater degree of swell- 

 ing and warping when the wood is exposed to a variable temperature. It cracks 



