f. 55 ] 



theatres arc more deceptive than more finilh- 

 cd works ; but this proceeds from the diftancc 

 and lamp light in which we view them. 



It is obfervable, that there are birds pecu- 

 liar to fome particular traéts of land, which 

 will not propagate or fpread themfelves into 

 other countries, though in the fame latitude, 

 and on the fame ifland, by which they might 

 very eafily extend themfelves, if one particular 

 place had not fomething in it, unknown to us, 

 which caufes them to continue where they are. 

 To inftance one amongft many, by way of ex- 

 ample : the Corntjh Chough, or Coracias of Al^ 

 drovandy is faid ,by Mr. Wtlloughhy, in his Or- 

 nithology, to breed on the clefts and rocks of 

 Cornwal, and on the coafts of Wales, and all 

 the weftern coafts of England. Yet I cannot 

 learn that there are any of them on the fouthern 

 coafts of England to the eaftward of Devon- 

 Ihire, nor on any part of the eaftern coafts ; 

 though thefe are in parallel latitudes to the 

 weftern coafts where thefe birds abound, and 

 the çoafts in many places have clefts and rocks 



feem- 



