and Obfervations 
287 
32. The Air-veJJ'els, Sap-vejfels , and Pores 
of Wood , are wonderful in their Figure, 
Number, andDifpofitionas plainly appears 
by fhaving off the thinned; Slices pofiible, 
lengthways, croffways, and obliquely, and 
bringing them to view. Fir and Cork are 
the readied: for this Purpofe : but all other 
Kinds of Wood, tho’ with fomewhat more 
Trouble, may be rendered fit'to be examin¬ 
ed. In a Piece of Cork, no longer than 
the eighteenth Part of an Inch, fixty Cells 
were numbered in a Row; whence it fol¬ 
lows, that one thoufand and eighty are in 
the Length of an Inch ; one million an hun¬ 
dred fixty and dx thoufand four hundred in 
an Inch fquare ; and in a Cubic Inch, one 
thoufand two hundred fifty-nine millions 
feven hundred and twelve thoufand 
In the Pith of Trees and Plants, cut fo as 
to become tranfparent, the Veffels may be 
difcerned diffindly. The Pores of Wood 
may likewife be feen advantageoufly in Char¬ 
coal and Small-coal. 
33. There are many Sorts of Sand; fome 
gathered on the Sea-fhore, or on the Shores 
of Rivers, and others found within Land. 
The Grains of each Sort differ much in Size, 
Hook’s Microg. p. 114 
V 3 
Form*, 
