REVIEWS 985 



lumber — those of the Hardwood Manufacturers' Association and 

 those of the National Hardwood Lumber Association. It may sur- 

 prise some to learn that the latter rules cover over 400 grades. For 

 grading softwood lumber there are a large number of different rules 

 in use. 



Statistics of the amounts of lumber manufactured and produced in 

 the United States are given in a number of tables at the end of the 

 book. It would seem that needless space has been given for this statis- 

 tical matter, as it is necessarily somewhat out of date, and current 

 values are published yearly by the Department of Agriculture. 



A valuable feature is the index in the back. 



The book should be in the library of every manufacturer of wooden 

 products, as well as that of structural engineers. 



H. D. T. 



Relative Resistance of Various Hardzvoods to Injection with 

 Creosote. By. C. H. Teesdale and J. D. McLean. Department of 

 Agriculture Bulletin No. 606. 



Experiments were made in a pressure cylinder and also with a 

 specially designed "penetrance apparatus" on most of the commercial 

 hardwoods to learn their relative resistance to treatment with coal tar 

 creosote. The results of the tests which are given m detail are useful 

 in grouping species for treatment so that species of similar resistance 

 may be treated together. G. M. H. 



Field Tests Made on Oil Treatment of Wood Against Marine 

 Borers. By C. H. Teesdale and L. F. Shackell. Eng. News-Record, 

 1917. Pp. 833-7. 



Service tests on samples of piling treated with various preservatives 

 by the Forest Products Laboratory indicate that creosote oil for 

 marine work should contain a large proportion of constituents boiling 

 above 320° C, as well as considerable amounts of high boiling tar acids 

 and bases. The specification for distillate oil for paving blocks 

 adopted by the American Wood Preservers' Association in 1917 is 

 considered the best standard specification for the purpose. 



Deep and uniform penetration of the preservative is necessary, as 

 spots of little or no penertation allow the borers access to the un- 

 treated interior. 



Xylotrya, which enter untreated wood and gain any appreciable 

 size, can then bore into treated wood and withstand considerable 

 quantities of preservative with impunity. 



Detailed results with various preservatives are given. 



G. M. H. 



