Vegetable Stanch . p 
reafon of the reciprocal proportion) that 34 
cubicle inches may pafs the Item in twelve 
hours 5 whence its velocity in the ftem will 
be 45 r inches in twelve hours, fuppofing 
there be no circulation nor return of the 
fap downwards. 
If there be added to 34, (which is the leaft 
velocity) r of it = 1 ii, this gives the greateft 
velocity, viz. 45f. The fpaces being as 3 : 4, 
the velocities will be 4 : 3 : : 45 t : 34* 
But if we fuppofe the pores in the furface 
of the leaves to bear the fame proportion, 
as the area of the fap veffels in the ftem do 
to the area of the ftem 5 then the velocity, 
both in the leaves, root and ftem, will be 
increafed in the fame proportion. 
A pretty exact account having been ta- 
ken, of the weight, fize, and furface of this 
plant, and of the quantities it has imbibed 
and perfpired, it may not be improper here, 
to enter into a comparifon, of what is taken 
in and perfpired by a human body, and this 
plant. 
The weight of a well ftzed man is equal 
to 160 pound: The weight of the Sun- 
flower is 3 pounds, fo their weights are to 
each other as 160 : 3, or as 53 : j. 
The 
