( 102 ) 
l?^s moifiure, the force:>aIl thefe Horizontal Vefsels together 
muft ufe towards the ^piration of the Bark from the 
Wood , will appear by this Calculation. Suppofe then 
that Fig. 4. is 7i . ot a Square Inch^ and that in the whole 
piece are but 2Coo Vefsels, which make in a Square Inch 
'14000CO Vefsels j that is 250000 Grains 5 this number 
divided by 10*40 ^ which is as many Grains as make a 
Pound, makes full 34 Pound, for the force which the 
Vefsels info fmall a piece of Wood come to exercife upon 
the Bark. When we examin the Bark thus torn from the 
Tree, we fliall fee the Upriiing Vefsels of which the Bark 
IS for the moft part conftituted, and which from thefirll 
formation went up ftreighr> and were placed regularly one 
by another, now in fome places lye wide from one another* 
and in Ibme clofer, but this is not the Natural Conftitution. 
We know that there is great difference between Oak 
wood growing in highland low ground^ or in coldjOr warmer 
Countries; or of flow or quick growth; but this piece here 
drawn was a clofe good wood, and therewith of a full 
growth. When we cut any wood through, in its length, 
fo that the cutting of the Knife cleaves the Horizontal 
Feflels afunder* it will feldom happen that the cutting of 
the Knife will handfomely cleave the vefsels. Bur. the Knife 
for the moft part cuts the Rifing and Horizontal vefsels a- 
flantj w^hich caufeth a falfe appearance :» as if the Rifing 
and Horizontal vefsels were knit one into ^ another.as Lin- 
nen or Bafket-work: and to cut the Horizontal vefsels 
crofs, we muft con<:eive the firft time, that the Knife is 
gone through the Center of the Tree or Bough, and the 
fecond time that the Knife is drawn parallel wt^^ the firft cut. 
vin Figure Sixth ABC D is reprefented a piece of 
Elnr wood /whieh to the naked Eye is as big as Figure E) 
and is what this Tree increafed in one year in thicknefs. 
'\ g Vr* Grew And Malpighi do botb rei^refm thsm inummn* 
r -A 
