58 THE NATURAL HISTORY 



on the wing at once; and, by a placid and easy flight, pro- 

 ceeded on southward towards the sea : after this I did not 

 see any more flocks, only now and then a straggler. 



I cannot agree with those persons that assert that the 

 swallow kind disappear some and some gradually, as they 

 come, for the bulk of them seem to withdraw at once : 

 only some stragglers stay behind a long while, and do 

 never, there is the greatest reason to believe, leave this 

 island. Swallows seem to lay themselves up, and to come 

 forth in a warm day, as bats do continually of a warm 

 evening, after they have disappeared for weeks. For a 

 very respectable gentleman assured me that, as he was 

 walking with some friends under Merton-wall on a 

 remarkably hot noon, either in the last week in December 

 or the first week in January, he espied three or four 

 swallows huddled together on the moulding of one of the 

 windows of that college. I have frequently remarked that 

 swallows are seen later at Oxford than elsewhere : is it 

 owing to the vast massy buildings of that place, to the 

 many waters round it, or to what else ? 



When I used to rise in a morning last autumn, and see 

 the swallows and martins clustering on the chimneys and 

 thatch of the neighbouring cottages, I could not help being 

 touched with a secret delight, mixed with some degree of 

 mortification : with delight to observe with how much 

 ardour and punctuality those poor little birds obeyed the 

 strong impulse towards migration, or hiding, imprinted on 

 their minds by their great Creator ; and with some degree 

 of mortification, when I reflected that, after all our pains 

 and inquiries, we are yet not quite certain to what regions 

 they do migrate ; and are still farther embarrassed to find 

 that some do not actually migrate at all. 



These reflections made so strong an impression on my 

 imagination, that they became productive of a composition 

 that may perhaps amuse you for a quarter of an hour when 

 next I have the honour of writing to you. 



