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fame altitude of the fun, in both latitudes, pro- 

 vided the pafîage is made in September or 

 March, but with nearly the fame degree of 

 heat. But if we confider, thaï there are many 

 birds of pafTage found far to the noitliward, in 

 feventy degrees of latitude (where, Î believe, all 

 the fowls are birds of paiKige, it not being a 

 climate fit for their fubfiftance in winter) they 

 mull have a long way to pafs, according to Mr. 

 Catefby's notion ; for feventy degrees to the 

 Equino6lial Line, and feventy degrees again to 

 the fouth of it, are an hundred and forty de- 

 grees, which, at our loweft computation of a 

 degree of latitude, make eight thoufand four 

 hundred miles, which is a prodigious flight for 

 a bird to peform in a fhort time. Birds that 

 are conil-anc inhabitants between the Tropics, 

 it is very likely, may make tranfits acrofs the 

 Equ:no6lial, to accommodate themfelves with 

 proper food at different feafons, or to avoid the 

 inconveniency of the excefTive rains in one place, 

 by feeking the more dry and pleafant feafons in 

 another ; but to imagine that birds who inha- 

 bit the high latitudes, either of the northern op 

 fouthernhemifphereSjfliQuld change their habita- 

 tions^ 



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