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THE NATURAL HISTORY 
cafe, in a river fo perpetually fifhed as the River 
? harries, the filhermen muft very frequently bring 
them up in their nets. 
It has been obferved, that the twigs upon which 
they have colledied, generally die. 
They leave this country, or at leaf!; difappear 
about the beginning of October; and it is fup- 
pofed they generally depart in the night, per¬ 
haps to be lei's expofed to the attacks of birds of 
prey; and that they avail themfelves of a fa¬ 
vourable wind, which mull wonderfully facilitate 
their paffage: when we confrder the velocity 
with which air balloons have been carried, mere¬ 
ly by the current of the air, at a little elevation, 
the difficulty of the migration of birds feems 
much leliened; and it has been obferved by 
Mr. Hebert, that Swallows, on their departure, 
rife into a higher region of the air. 
in the Iflands ofRieres, which are on the foufh 
coaft of France, where the weather is always tem¬ 
perate, and a perpetual fpring is enjoyed, Swal¬ 
lows have been feen all the winter; there they 
have found their infect food. They roofc upon 
the orange trees, and injure that delicate plant. 
A Swallow has been employed like a Carrier 
Pigeon; the female was taken from her neff, 
to the place from which the intelligence was to be 
feat, and a thread of a certain colour, and a cer¬ 
tain 
