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

 vided the pafTage is made in September of 

 March, but with ncdrly the fame degree of 

 heat. But if we confider, that there are many 

 birds of paiTage found far to the northward, in 

 feventy degrees of iacitude (where, I believe, all 

 the fowls are birds of paffage, it not being a 

 climate fit for their fubfiftance in winter) they 

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

 Caieiby's notion -, for feventy degrees to the 

 Eqj;noftiaf 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 confiant inhabitants between the Tropics, 

 it IS very likely, may make tranfits acrofs the 

 Equinoflial, to accommodate themfelves with 

 proper food at different feafons, or to avoid the 

 inconveniency of the excefTive rains in one place, 

 by leeking the more dry and pleafant feafons in 

 another -, but to imagine that birds who inha- 

 bit the high latitudes, either of the northern or 

 fouthernhcmifpheresjfhouid change their habita- 

 tions, 



