/ 
35 2 ^ yegetation. 
cxpofed to a free drying air, they perfpife 
plentifully, and thereby drawing the fap to 
the top, they advance much in height : But 
^oke ^'erfa, if when fuch a Grove of tall 
* trees is cut down, there be left here and 
there a fingle tree, that tree will then fhoo't 
out lateral branches j the leaves of which 
branches now perfpiring freely, will at- 
tract plenty of fap, on which account 
the top being deprived of its nourifliment, 
it ufually dies. 
And as trees in a Grove or Wood grow 
only in length, becaufe all the nourilhment 
is by the leaves drawn to the top, moft of 
the fmall lateral fhaded branches in the mean 
time perilhing for want of perfpiration and 
nutrition 5 fo the cafe is the very fame in the 
branches of a tree, which ufually making 
an angle of about 45 degrees with the ftem 
of the tree, do thereby beautifully fill up at 
equal and proper diftances the fpace between 
the lower branches, and the top of the tree, 
forming thereby as it were a parabolical 
Grove, or Thicket 5 which fhading the arms, 
the fmall lateralfiiocts of rhofearms ufually 
perifia for want of due perfpiration 5 and 
therefore the arms continue naked like the 
bodies 
