18 BULLETIN 1050, U. S. DEPARTMENT OF AGRICULTURE. 



Specific gravity. — The ratio of the weight of a piece of wood (or 

 other substance) , usually oven-dry, to the weight of an equal volume 

 of water, with the latter considered as 1. (For most woods the 

 specific gravity is less than 1, because they are lighter than water, 

 which weighs nearly 62.5 pounds per cubic foot.) 



Storied rays. — Rays arranged in horizontal layers or stories in the 

 tree, producing "ripple" marks on tangential faces. (See fig. 12.) 



Summe7-tvood.— -The outer, often darker and harder portion of 

 each annual ring. 



Tange7itial. — Along a tangent, or at right angles to the radius. 



Tangential surface. — A longitudinal surface cut approximately at 

 right angles to the rays, equivalent to flat grain or plain-sawed 

 surface. 



Tyloses. — Glistening, froth-like ingrowths in the pores of the 

 heartwood, closing them up more or less. 



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