Philosophical Transactions/Volume 4…
“ In all Trees the Gravity promotes the Bleeding; so that from a Branch or Root, that bendes downward, there will issue a great deal more Sap, than from another of the same bigness in a more erect posture. 3. Branches and Young trees cut quite off when they are full of Sap, and held perpendicularly, will bleed; as we experimented in Willow, Birch, and Sycamore: And if you cutt off their tops, and invert them, they will bleed also at the little ends. Hence one may conjecture, that the narrowness of the pores is not the sole cause of the Ascent of the Sap ”
