on the Descent of the Sap in Trees . 289 
experiments, I found that the coloured infusion had passed 
through an elaborate series of vessels between the cortical and 
alburnous substances, and that many minute ramifications of 
these vessels approached the external skin at the base of the 
buds, to which, as to every other part of the growing tuber, I 
conclude they convey nourishment. 
Some other experiments were made on this plant, which 
appeared to me interesting ; but my Paper has already a good 
deal exceeded its intended limits. I will therefore dismiss the 
subject ; but intend to trouble you with another Memoir in the 
autumn, should this be honoured with the approbation of the 
Royal Society. 
I am, &c. 
T. A. KNIGHT, 
Elton, 
March 26, 1803. 
