550 Forestry Quarterly. 



made on material from just this source, which was the only one 

 available at the time, would not have added materially to the 

 value of the results. 



A comparison of averages from the above test results with 

 those given in Table 2, page 21, U. S. Forest Service Bulletin 

 108, on similar timber air seasoned for two years, shows the 

 following facts : 



1. Small pieces of the long-seasoned Douglas fir without de- 

 fects are 490 pounds per square inch stronger in longitudinal 

 shear than two-year-air-seasoned material, which has an average 

 resistance of 822 pounds per square inch. This represents an 

 increase in shearing strength of about 60 per cent. 



2. The modulus of elasticity in bending for the long seasoned 

 Douglas fir is 20 per cent, higher. 



3. The fiber stresses at the elastic limit and at the maximum 

 load for the long seasoned material are respectively about 30 per 

 cent, and 13 per cent, higher. 



4. The maximum crushing strength in compression longitudi- 

 nally is 40 per cent, higher for the long seasoned Douglas fir, but 

 its elastic limit is 30 per cent, higher. 



5. The longitudinal crushing strength of the long seasoned red- 

 wood is 25 per cent, greater. 



"In conclusion, the well preserved condition of the floor joists 

 shows that proper ventilation will prevent the decay of timber 

 that is exposed to a damp atmosphere. The absence of dry rot 

 in the wall studding shows that air has sufficient access through 

 channel rustic to prevent it. Under favorable service conditions, 

 such as in the ordinary frame building, sound heart timber in 

 pieces of moderate section gradually gains in strength and stiff- 

 ness through air seasoning." 



S. J. R. 



Uses of Commercial Woods of the United States: Beech, 

 Birches and Maples. By H. W. Maxwell. Bulletin No. 12, U. 

 S. Department of Agriculture, Washington, D. C. 1913. Pp. 56. 



This publication is one of a series on the uses of woods be- 

 gun by the Forest Service a few years ago. The first two pub- 

 lications related to the cedars, cypresses and sequoias, and to 

 the pines. This is the first dealing with hardwoods and the 



