APPENDIX. Ill 



as this steam or vapour rises from the root, its own 

 natural quality carries it upwards to meet the air; 

 it enters then the mouths of the several arterial 

 vessels of the tree and passeth up them to the top, 

 with a force answerable to the heat that put it in 

 motion. By this means it opens, by little and 

 little, as it can force its way, the minute vessels 

 which are rolled up in the buds, and expand them 

 by degrees into leaves. But as every vapour of 

 this kind, when it feels the cold, will condense 

 and thicken into a water, so when the vapour 

 which I mention to rise through the arterial ves- 

 sels arrives at the extreme parts of them, i. e. the 

 buds of a tree, it there meets with cold enough 

 to condense it into a liquor, as the vapour in a 

 still is known to do. In this form it returns by 

 means of its own weight to the root down the 

 vessels, which do the office of veins, lying be- 

 tween the wood and inner bark, leaving, as it 

 passeth by, such parts of its juice as the texture 

 of the bark will receive and requires for its sup- 

 port. It may be wondered at, that I have not 

 taken more notice of the pith, which has been 

 always accounted the principal part of a tree ; to 

 which I shall only answer at this time, that many 



