SIGNS OF RAIN. 
141 
swallows fly high, and the smoke goes 
straight up.” 
“ Neither of them can be always de¬ 
pended upon.,” remarked Mr. Winston.. “I 
have seen swalknvs flying almost out of 
sight in a thunder-storm ; and I have seen 
the smoke going straight up not five 
minutes before a rain which lasted all day. 
Still, generally speaking, it may be said 
that swallows fly low, and, as it were, skim 
the ground, before rain.” 
“ Why do they do so ?” asked Daisy. 
“ I suppose, the upper regions of the air 
becoming colder, the insects are driven to 
seek the surface of the earth and the swal¬ 
lows come down after them. You know 
when they are flying in circles they are 
seeking their prey.” 
“ And how about the smoke going up?” 
asked Sidney. 
“ The air being lighter before rain and in 
damp weather, the smoke cannot float in it, 
and falls to the ground; while in fine, dry 
weather the air is heavier than the smoke, 
and sustains it as the coffee in this cup sus¬ 
tains this piece of toast. If I should put 
the toast into ether,—which is a very light 
