- 
( (35%) 
the Willow eutting was planted, could absorb thesé 
matters through the pores of the wooden box which 
contained ‘it, and that a @lass case could alone have 
prevented such absorption. Hunter, finding that 
oil and salt entered into the composition of plants, 
concluded that these formed their principal food, 
and accordingly recommended, as the great deside- 
ratum i agriculture, an oil compost. Lord Kaims 
attempted to revive the expiring creed of Lord Ba- 
con, but finding from Hales’ statics, that one third 
of the weight of a green pea was made up of car- 
bonic acid, he added air to the watery aliment of the 
English philosopher—but entirely rejected oi! and 
earth, as too gross to enter the mouths of plants, 
and salt, as too acrid to afford them nourishment. 
Quackery, which at one time or other, has made its 
way into all arts and sciences, could not easily be 
excluded from agriculture. Hence it was that the 
Abbe de Valemont’s prolific kquor, and De Hare’s 
and De Vallier’s powders, &c. &c. were believed 
to be all that was necessary to vegetation, and found 
the more advocates, as they promised much and 
cost little. But before the march of modern chemis- 
try, quackery could not long maintain itself; and 
from the labors of Bennet, Priestly, Saussure, In- 
genhouz, Sennebier, Scheder, Chaptel, and Davy, 
&ec. &c. few doubts remain on this important sub- 
ject. - These will be presented in the course of the 
following inquiry. | 
I. Of earths, and their relation to vegetation. 
Of six or eight substances, which chemists have 
denominated earths, four are widely and abundant- 
