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riable vicissitudes of our high latitudes have settled 

 into spring ? None of these are lulled to forgetfulness 

 by solar animation and an evergreen livery. They 

 require no alarum to awaken their vigilance and sum- 

 mon them to depart. " They know their appointed 

 time." In vain does the perennial hum of insect life 

 tempt the swallow to stay ; she is deaf to the siren 

 charmer, and hastens to occupy her place in the ca- 

 lendar of her destinies. The direction of her flight 

 is not the least wonderful in the history of migration. 

 Instinct wisdom accomplishes what reason and expe- 

 rience illuminated by science achieved after the lapse 

 of ages. The swallow has no compass for her guide ; 

 and the stars are useless, since another hemisphere is 

 there revealed. The carrier pigeon flies at the rate 

 of 50 miles an hour, but the velocity of the swift 

 has been calculated at 250 miles an hour ; and Mr. 

 Montagu in his Ornithological Dictionary says that 

 the swift (hirundo opus) " can and does suspend 

 itself in the air for fourteen or fifteen hours together;" 

 and really, except on the wing, we know not a more 

 helpless creature. At this calculation it would in fifteen 

 hours fly over a space of 3750 miles, and might there- 

 fore leave England at 6 A. M., ere insect life were well 

 awake, and at noon be fluttering round the palm trees 

 of Africa. We have seen the swallow (hirundo rus- 

 tica) in Italy, after their disappearance in this country, 

 and two once settled on the rigging of our vessel in the 

 Mediterranean. They have been seen at sea in numbers; 

 and the reason why they have not been more frequently 

 observed is, that, whether in their exit or return, 

 night is in all probability the period of migration ; and 

 the loftiness of their flight, where no local causes 

 concur to disturb their progress, would render them 

 invisible to the eye of the spectator. "On a calm 

 F 5 



