THE INFLUENCE OE PLANTS IN EOOMS. 225 
are temporarily subjected to an abnormal amount 
of heat, we all know the eagerness with which we 
seek for cool, soft, and congenial vapours. Gentle 
moisture softens, cools, and refreshes the skin. 
Is it not, for instance, delicious to go, in the hot 
summer, into a cool greenhouse ? Yet, knowing 
and granting all this, we still suffer ourselves to 
be suffocated and—in a degree—scorched by the 
hot, dry air of our dwelling-rooms. In our dis¬ 
tress, on hot summer days, we open our windows 
to admit—what? The hotter external air. We 
fan ourselves, and by the process—unreflecting as 
we are—we simply set the warm atmosphere of 
our rooms into motion against the warmer sur¬ 
faces of our bodies, the result being a very slight 
and temporary relief, followed immediately by an 
increase, to the extent of the warmth extracted 
from ourselves, of the heat of the air immediately 
surrounding us. Sometimes we resort to the 
effectual, but clumsy and inconvenient expedient 
of hanging wet sheets against our windows on the 
inside. 
But why all this trouble P Why do we not 
follow the simple teaching of Nature, and sur- 
