Current Literature. 221 



the practical inefficiency of herding goats over chapparal for the 

 destruction of the same, when the financial interest of the goal 

 herder and not merely the silvicultural result is considered. 



In a report on a study of the character of mechanical failure 

 of wood, the interesting statement is made that in tension tests 

 moisture conditions have no influence. In spite of the fact that 

 this confirms the findings recorded in Bulletin 8 of the Forestry 

 Division, the reviewer remains a doubting Thomas and finds 

 the explanation in the almost impossibility of devising a true 

 tension test in wood. 



A somewhat doubtful formula for determining the relative 

 value of fuel wood compared with coal, makes the cost of wood, 



c = 1_, in which a is the cost of coal; b, the heating value of 



2000 



wood as compared to that of coal, a table for a number of Ari- 

 zona species being given, and x, pounds of wood per cord ; the 

 2000 being the weight of a ton of coal. 



Interesting statistical data are brought regarding the produc- 

 tion and market conditions of the hardwood distillation industry, 

 bringing out the fact that the smaller by-products of distillation 

 find no ready market; only two plants report selling tar or tar 

 products, namely one selling wood oil for 8.5 cents and wood 

 creosote and wood tar at 4.5 cents per gallon, the other, unspeci- 

 fied products at 8 cents a gallon. 



An investigation into the efifect of sowing poisoned wheat with 

 tree seed to keep down loss from birds, furnished mainly nega- 

 tive results- Treating seeds with red lead, the usual method 

 in Europe, was also found ineffective. Screening with wire 

 screens, which is effective, is too expensive. 



The beneficial influence of brush on natural regeneration by 

 conserving soil moisture is one of those matters which is most 

 difficult to prove, since so many other variables enter the prob- 

 lem. 



The question of locality of seed supply, which is now so 

 thoroughly investigated by European Stations has also been sub- 

 jected to inquiry with Pinus ponderosa seed. The method of 

 this experiment is not convincing, and when the conclusions are 

 at variance with conclusions from other experiments they must 

 be taken with great caution. It must not be forgotten that all 



