io6 Forestry Quarterly. 



State Board of Forestry. A brief discussion of the factors 

 influencing growth is followed by two volume tables, one of which 

 is in cubic feet and the other in feet board measure, for Blue Gum 

 {Eucalyptus globulus). Detailed data on each grove inspected 

 occupies the greater part of the bulletin. 



The Effect of the Speed of Testing upon the Strength of Wood 

 and the Standardisation of Tests for Speed. By Harry D. 

 Tiemann. Reprint, Proceedings of the American Society for 

 Testing Materials, Vol. VIII, 1908.* 



It has long been a recognized fact that wood has a greater 

 resisting power to immediate stresses than to more permanent 

 loads. This paper embodies results of research to determine the 

 fundamental laws underlying the relations of time and strength. 



Following is an epitome of Mr. Tiemann's deductions : 



1. Tests, in order to be intelligently compared, must take into 

 account the speed at which the stress was applied. 



2. In determining basis for a ratio between time and strength 

 the rate of strain, which is controllable, and not the rate of stress, 

 which is circumstantial, should be used. 



3. This ratio or "speed strength modulus" may be expressed as 

 a coefficient which, if multiplied into any proportional change in 

 speed, will give the proportional change in strength, at any given 

 speed. This ratio is derived from empirical curves. 



4. Green and wet wood show greater change in strength than 

 dry wood. 



5. The following speeds expressed as rates of fiber strain (Z) 

 in ten-thousandths of an inch per minute per inch of length of 

 fiber, have been proposed as standards : 



Bending Z = .0015 in. per min. pci- in. 



Compression Z =: .0015 



Shearing Z = .0100 " " " " 



6. At least 50 per cent, change in speed may ordinarily be 

 permitted without correction since the same could not cause the 

 load to vary more than 2 per cent. Care should be exercised, 

 however, to secure uniform speed throughout the test. S. J. R. 



* This article was reviewed in F. Q. vol. VII, p. 100, but we bring this 

 addition for the information it contains. 



