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incapacitated for this Work* but then the Length 
of their Wings enables them to prey on numberlefs 
flying Infeds, with which the Air is ftored during 
the warm Months : And it is obfervable, that not 
only Swallows, but mod other Summer Birds of Paf- 
fage feed, on the Wing, on fuch-like Infeds as are 
feen no more when cold Weather begins to come. 
The various Conjectures concerning the Places 
whereto Birds of Paflage retire, are occafioned by the 
Want of ocular Teftimony to bring the Matter to 
feme Certainty. But if the Immenfenefs of the 
Globe be considered, and the vaft Trads of Land 
which ftill remain unknown, unlefs to their own 
barbarous Inhabitants, it is no Wonder we are yet 
unacquainted with the Retreat of thefe itinerant Birds, 
If I may be allowed to offer my own Sentiments, I 
cannot but agree in the general Opinion of their 
palling to other Countries by the common natural 
Way of flying, with this additional Conjedure* viz, 
that the] Places, to which they retire, lie probably 
in the fame Latitude in the Southern Hemifphere 
as the Places from whence they depart * where the 
Seafons reverting, they may enjoy the like agreeable 
Temperature of Air. 
It may be objeded, that Places of the fame Lati- 
tude in the Southern Hemifphere may be divided by 
too wide a Trad of Sea for them to pafs over. But 
why then may not feme other Parts of the Southern 
Hemifphere ferve their Turn ? Thisfeems more rea- 
fonable to me, than that they fhould remain on our 
Side of the Northern Tropic* within a few Degrees 
of which, at the Winter Solftice, it is fo cold, as 
frequently to produce Snow * which, by dilperfing 
fuch 
