140 
MISCELLANEOUS. 
[Part II. 
pose this root to increase only 5 -in. in diameter 
each year, — in less than a century, that is in 
ninety-six years, it will be even with the surface, 
and in another century it will be one foot above 
the surface. Without contravening circum¬ 
stances, this rising of the roots may be seen 
around all old trees. 
In the growth in girthing of the roots, the 
earth above the roots is easily displaced, that on 
the sides with more difficulty, and the earth 
below roots with still greater difficulty. In 
proportion, then, as the surface against which the 
lower sides of roots grow is unyielding, each 
root has a tendency to upheave itself bodily , be¬ 
sides the rising at its upper surface from what is 
called the growth by juxta-position; and the 
whole mass of roots have a tendency to upheave 
the whole tree. In the case of roots growing on 
rock this upheaval must take place, or the roots 
must cease to grow on their lower sides. 
In the observation above in regard to the 
lateral upward growth of roots, credit is only 
taken for half of the growth in diameter, that is, 
for l- 8 th of an inch growth, on the upper side of 
the root. The other l- 8 th of an inch growth on 
the lower side is supposed to displace the earth 
downward. I think it, however, likely, in the 
