REVIEWS 1085 



each tree varied from 40 to 120, depending upon the size of the tree, 

 though in the case of some species, such as elder (Sambuciis glauca), 

 a much smaller number of tests was undoubtedly made. The number 

 of trees of each species from which test specimens were obtained varied 

 from 2 to 60. The actual number of tests in each case is, however, not 

 stated. The bulletin contains a description of the methods used in mak- 

 ing the tests, which practically duplicates a portion of Circular 38, "In- 

 structions to Engineers in Timber Tests." This is justifiable in view 

 of the lack of understanding on the part of many commercial concerns 

 of the methods used bv the Forest Service in timber testing. 



B. L. G. 



The Substitution of Other Materials for Wood. By Rolf Thelen. 

 U. S. Department of /Vgriculture, Report No. 117. Contributed by the 

 Forest Service. Pp. /8<. 



This report contributes valuable data on the relative increase in use 

 of wood and other materials in certain fields. The word substitution 

 is in many of the fields a misnomer, since no one can say which of the 

 materials used acquired priority rights, as it were. Hence a better title 

 might have been, "The Relative Increase or Decrease in the Use of 

 Wood as Compared with Other Materials in the Same Field." Graphic 

 methods are used in presentation of much of the data, so that the results 

 of the investigations may be seen at a glance. In regard to prices, it is 

 shown that lumber increased faster than other commodity prices prior 

 to 1907 ; since then scarcely as fast. Also per capita consumption in- 

 creased prior to 1907, but since then appears to be falling ofl:. As to 

 the total national use of the various commodities, lumber has been fall- 

 ing off somewhat since 1907. Common red brick has fallen off in the 

 same period. Use of iron and steel shapes has increased slowly, while 

 the use of cement has increased rapidly. It is admitted, however, that 

 this does not at all indicate displacement of wood, and this point needs 

 special emphasis. In the field of minor uses, metal trim and metal fur- 

 niture, steel and part steel freight cars, ships and vehicles, where in 

 most cases wood has decreased in these fields. As to roofing materials, 

 wooden shingles show a gradual decrease, while substitutes show a con- 

 stant increase in use. In box making and allied uses, pulp boxes are 

 making inroads on the use of lumber boxes. In paving and pipe, use 

 of wood seems to be on the increase. The total substitution claimed is 

 summarized in Table 24 at 27,715,000,000 for wood in all forms, in- 

 cluding fuel, and the substitution for lumber 8,090,000. Much of this. 



