20G EYES OF INSECTS, 
quickness of thought, and either side- 
ways^ or up and down ; and thus we are 
saved the continual trouble of turning 
the head. We are also furnished with 
eyelids, by closing which, we protect 
those tender organs from dust, from in- 
juries, and from too strong a glare of 
light; and these eyelids are fringed with 
short hairs, which, in some measure, 
answer the same purposes, while the lids 
remain open ; but no insects have eye- 
lids. 
Lucy. Then, I should think, that 
their eyes must often be. hurt by the clay 
and stones, which they unavoidably meet 
with under ground. 
Mother, For that reason the outer 
coat or covering of their eyes is very 
hard, resembling horn in strength, but 
as transparent as glass. 
Lucy, You said, that the little pro- 
jections enabled the animal to see in 
every direction, as well as if it could 
move its eyes ? 
Mother, Feel this magnifying glass. 
