UTILIZATION* OF DOGWOOD AND PERSIMMON 
13 
In dogwood the rays, often called medullary rays, which serve 
for food conduction and storage, are not conspicuously broad, but 
on the smoothly cut end surface of the wood they can be seen dis- 
tinctly as fine radial lines slightly lighter colored than the sur- 
rounding wood. In a cross section of a tree trunk rays may be 
compared to the spokes of a wheel. They vary in width, and the 
larger ones are somewhat wider than the largest pores, which ordi- 
narily can not be seen with the naked eye. The rays of persimmon 
are very fine, even under a hand lens. 
PHYSICAL AND MECHANICAL PROPERTIES 
Dogwood and persimmon are very heavy, very hard, and only 
fairly straight grained. They are worked (cut, carved, shaped) 
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Fig. 
-Cross sections of dogwood (left) and persimmon (right) magnified 38 diameters 
only with difficulty, and they do not glue easily. The wood of each 
is tough and resistant to abrasion. Under continuous wear both 
become extremely smooth, although the dogwood being finer tex- 
tured becomes the smoother of the two. The property of becoming 
extremely smooth is one of the most important in shuttles and 
makes dogwood and persimmon superior to such woods as hickory, 
oak, or maple for this purpose. 
Dogwood squares of average shuttle-block size that contain the 
pith of the tree are liable to split or burst open during seasoning. 
This is caused by certain internal stresses that are set up in the wood 
as it dries. * Pieces larger than shuttle blocks, such as those used for 
bobbin or spool heads, pulleys, and mallets, may contain the center 
or pith without danger of splitting. Bursting or checking is experi- 
enced with bolts as large as 4 to 8 inches in diameter in green condi- 
tion if they are exposed to the hot sun, but this bursting does not 
