The vegetable SYSTEM. 
3 
Thus we fee a great deal is owing to Heat ; but It is not fo much 
as has been thought : for the fame climates, countries in remote 
parts of the earth where the degree of Heat is alike, do not produce 
the fame Plants ; but often the mofl; different. Rome and Pekin 
are nearly in the fame latitude, but what can be more different than 
the Italian and Chinese Plants? The Cape of Good Hope 
may be matched In latitude by different places ; but no where in 
its Vegetables : they are peculiar, and diflindt from thofe of all the 
world ; and are perhaps more beautiful. In thefe places the heat 
is nearly equal, but the Plants are different s the air has the fame 
warmth, but Vegetation takes .quite another courfe. Therefore we 
are to feek the variation in fome other caufe ; and naturally in the 
other Elements. 
CHAP. II. 
Of the Effects of Air in Vegetation. 
A I R is not lefs neceflary to Plants than Fire. When fhut up 
from it entirely, they die equally ; or when it is withdrawn 
from them In lefs degrees, they fade in proportion. Seeds will 
not grow in the receiver of an air pump, when carefully exhaufled ; 
and vigorous young plants die. 
Vegetables will live in the fame quantity of confined Air 
much longer than animals ; for they fill it lefs by their cool perfpi- 
ration, but it is only for a certain time they will bear it. If a 
Sprig of Mint be fet in water in a bottle open, and a like one in a 
bottle corked, they will for many days grow with equaul vigour; 
but afterwards the Plant that is corked up will begin to fade : its 
Juices flagnate, mouldynefs appears upon its extreme parts, and it 
dies. Therefore not only Air, but a free Air is neceffary to Plants ; 
and Vegetation is affected by all its changes, and its natural difi'er- 
cnces. 
T HE 
