436 



wood, are strongest. Crossgrained and knots reduce both stiffness 

 and strength. A crossgrained piece will scarcely support one-twen- 

 tieth of the load that a straight-grained piece of the same kind will 

 support. (Y. B. 1895.) 



Effects of Seasoning Timber. A cord of green wood weighs 

 50 per cent more than when air dry. A cord of well-dried wood 

 still contains 600 pounds of water. In the burning of green wood, 

 nearly one-half the heat is lost in evaporating the water contained 

 in it. One-half the weight of fresh, sappy pine is due to water. 

 The kiln-drying of lumber, at a small expense, saves 1,000 to 1,500 

 pounds of freight per 1,000 feet, B. M. Seasoning increases stiff- 

 ness and strength by about 50 per cent. Checks produced in dry- 

 ing decrease the value of timber; seasoning, therefore, always in- 

 jures as well as benefits. Wood always swells and shrinks that is, 

 takes up and gives off water hence the periodic recurrence of 

 cracks in floors, etc. Split wood shrinks more evenly, sheds water 

 and wears better than if sawed. Good hard pine shrinks about 6 

 inches per 100 inches width of flooring when laid green ; good red 

 oak about 9 inches. A "quarter-sawed" board shrinks only one- 

 half to two-thirds as much as a bastard-sawed one. Wood shrinks 

 inappreciably in length, 3 to 6 per cent in radial direction (across 

 the rings), and 4 to 10 per cent in tangential direction (with the 

 rings). Quarter-sawed boards and bastard-sawed boards neither 

 shrink nor wear alike ; hence for the best floors they should not be 

 used side by side. (Y. B. 1895.) 



Stiffness and Strength of Timber. Doubling the length of a 

 board or timber reduces the stiffness eightfold and the strength one- 

 half. Doubling the width of a board doubles the stiffness and 

 strength. Doubling the thickness of a board or the depth of a 

 timber increases the stiffness about eightfold and the strength four- 

 fold. If, therefore, it is desired to double the length and retain the 

 same stiffness, it is necessary to double the thickness or depth. 

 Weight for weight, a stick of pine is stronger and stiffer than solid 

 iron or steel of same shape and length. A joist 2 by 6 inches is 

 three times as stiff as one 2 by 4. A joist 2 by 8 inches is eight 

 times, and one 2 by 12 is twenty-seven times, as stiff. A good hard- 

 pine joist 2 by 4 inches and 10 feet long may support 2,000 pounds 

 in the middle, but it can safely be trusted only to the extent of 400 

 pounds. If weighted suddenly, a timber bends much more than if 

 weighted gradually with the same weight. A timber projecting 

 from the wall and weighted at the end (a cantilever) supports only 

 as much as a timber twice the length resting on both ends and 

 weighted in the middle. (Y. B. 1895.) 



FORESTRY ORGANIZATION. 

 This list is made up from the latest obtainable information. 



Name of Organisation. Address 



Appalachian Mountain Club Tremont Bldg., Boston. 



Arizona : 



Salt River Valley Water Users' Association Phoenix. 



California: 



Water and Forest Association 1405 The Merchants Exchange 



Bldg., San Francisco. 



