14 Vegetable Static ks. 
In a long dry feafon, therefore, efpecially 
within theTropicks, we muft have recourfe 
for fufficienc moifture (to keep Plants and 
Trees alive) to the moift ftrata of earth, 
which lay next below that in which the 
roots are. Now moift bodies always com- 
municate of their moifture to more dry 
adjoining bodies 5 but this flow motion of 
the afcent of moifture is much accelerated 
by the Sun’s heat to confiderable depths in 
the earth, as is probable from the following 
aoth Experiment. 
Now 180 grains of Dew falling in one 
night, on a circle of a foot diameter, — 
1 13 fquare inches; thefe 180 grains being 
equally fpread on this furface, its depth 
1 80 
will be tt 7 part of an inch = — — — — „ 
113x254 
I found the depth of Dew in a winter night 
to be the part of an inch ; fo that if we 
allow 1 5 1 nights for the extent of the fum« 
mer’s Dew, it will in that time arife to one 
inch depth. And reckoning the remaining 
214 nights for the extent of the winter’s 
Pew, it will produce 2. 39 inches depth, 
which makes the Dew of the whole year 
amount to 3. 39 inches depth. 
And the quantity which evaporated in a 
