appendix. 267 
ill Effe£ls of which are frequently prevented 
by cutting out the cankered Part, 
Observation IX. 
I. T Have in many Inftanccs (hewn that Air 
X freely enters the Veffels of Trees, and 
that it is in a great Abundance wrought into 
their Subftance. §iu. May nottheUfeof thofe 
fpiral Wreaths that are coiled round the Infides 
of thofe Veffels which are fuppofed to be Air 
Veffels, and which are manifeftly to be feen 
in feveral Trees, as alio in the Leaves of the 
Vine and of Scabious, may not thefe be de- 
figned by Nature to promote the quicker Af- 
cent of Air, by being in fome Meafure con- 
formed to its elaftick Contortions ? For fuch 
fpiral Wreaths feem to be altogether ufeleft, 
for promoting the Afcent of any Liquor, as 
the Sap which afcends mod freely thro’ in- 
numerable other capillary Veffels which have 
no fuch fpiral Coils in them. Not that we 
arc to fuppofe the Air in its elaftic State aftu- 
ally to touch, and thereby to be determined 
in the Courfe of thefe Spirals as any Liquor 
would be. But as the Rays of Light when 
they are reflefted froma folid Body, are found 
to 
