56 THE NATUEAL HISTORY 



But this is making use of a violent piece of machinery : it is 

 a difficulty worthy of the interposition of a god ! " Incredulus 

 odi." 



TO THOMAS PENNANT, ESQUIRE. 



THE NATURALIST'S SUMMER-EVENING WALK. 



equidem credo, quia sit divinitus illis 



Ingenium. ViRG. Georg. 



WHEN day declining sheds a milder gleam, 



What time the may-fly * haunts the pool or stream ; 



When the still owl skims round the grassy mead, 



What time the timorous hare limps forth to feed ; 



Then be the time to steal adown the vale, 



And listen to the vagrant 2 cuckoo's tale ; 



To hear the clamorous 3 curlew call his mate, 



Or the soft quail his tender pain relate ; 



To see the swallow sweep the dark'ning plain 



Belated, to support her infant train ; 



To mark the swift in rapid giddy ring 



Dash round the steeple, unsubdu'd of wing : 



Amusive birds ! say where your hid retreat 



When the frost rages and the tempests beat ; 



Whence your return, by such nice instinct led, 



When spring, soft season, lifts her bloomy head ? 



Such baffled searches mock man's prying pride, 



The GOD of NATURE is your secret guide ! 



have found in land-bridges, even between distant continents, and how seldom 

 a land-bridge will bear the weight of any other foot than that of the speculator who 

 made it, will share White's distrust. We now expect the constructor of land- 

 bridges to attend to distances and soundings, and to bear in mind the great 

 stability of the larger land-masses. Practical identity of flora and fauna on both 

 sides of a strait may prove former land-connection, but it is a very different thing 

 to infer such connection from the occurrence of a few species, even though closely 

 allied, in widely distant lands.] 



1 The angler's may-fly, the ephemera vulgata, Linn., comes forth from it's 

 aurelia state, and emerges out of the water about six in the evening, and dies 

 about eleven at night, determining the date of it's fly state in about five or six 

 hours. They usually begin to appear about the 4th of June, and continue in 

 succession for near a fortnight. See Swammerdam, Derham, Scopoli, &>c. 



2 Vagrant cuckoo ; so called because, being tied down by no incubation or 

 attendance about the nutrition of it's young, it wanders without control. 



3 Charadrius oedicnemus. 



