On natural Phcenomena, 341 



SWALLOW. They are guiltless of depredations on our 

 valuable products; and are destroyers of flies, and 

 other insects which annoy us. Although their nests, 

 and visitations in our chimneys, are unpleasant ; their 

 arrival and departure are thereby the more strongly 

 marked, and more evidently perceived. They aban- 

 doned our houses uncommonly early in the last au- 

 tumn. Soon after their arrival in the spring ; when 

 they are in large and countlessly numerous flocks, 

 frequenting hollow trees, chimnies, and caverns ; they 

 separate for- breeding. So that they are not observed 

 in numerous assemblage, until the chilly nights of au- 

 tumn arrive. They then, with the reinforcements of 

 their young, produced through the summer, congre- 

 gate ; and again frequent, previously to their depar- 

 ture, their usual places of rendezvous ; unless some 

 disturbance to their former place of assemblage had 

 been given : in which case they seek another point of 

 collection for the occasion.* The places of their na- 



" So the boat's brawny crew the current stem, 



" And, slow advancing, struggle with the stream ; — 



" But if they slack their hands, or cease to strive, 



" Then down the flood, with headlong haste, they drive. 



* It would be endless, and probably, by some, not credited, to 

 enumerate many instances of the vast numbers of chimney siuaU 

 loius^ resorting to one place of rendezvous. I content myself with 

 giving one indubitable account, related by some of the most re- 

 spectable inhabitants of Merioru Mr. J. Williams is among the 

 best characters in Montgomery county ; and lives near the gulf, in 

 U/ifier Merion, The following is an extract of a letter I have 



