248 NATURAL HISTORY 



water, and the fishes swimming in a circle round it. The 

 simple exhibition of the fishes is agreeable and pleasant ; but 

 in so complicated a way becomes whimsical and unnatural, 

 and liable to the objection due to him, 



" Qui variare cupit rem prodigialiter imam." 



I am, &c. 



LETTER LV. 



TO THE SAME, 



October 10, 1781. 

 DEAR SIR, 



I THINK I have observed before that much the most consider- 

 able part of the house-martins withdraw from hence about the 

 first week in October; but that some, the latter broods I am 

 now convinced, linger on till towards the middle of that 

 month : and that at times, once perhaps in two or three 

 years, a flight, for one day only, has shown itself in the first 

 week of November. 



Having taken notice, in October 1780, that the last flight 

 was numerous, amounting perhaps to one hundred and fifty ; 

 and that the season was soft and still ; I was resolved to pay 

 uncommon attention to these late birds ; to find, if possible, 

 where they roosted, and to determine the precise time of their 

 retreat. The mode of life of these latter hirundines is very 

 favourable to such a design ; for they spend the whole day in 

 the sheltered district, between me and the Hanger, sailing 

 about in a placid, easy manner, and feasting on those insects 

 which lore to haunt a spot so secure from ruffling winds. 

 As my principal object was to discover the place of their 

 roosting, I took care to wait on them before they retired to 

 rest, and was much pleased to find that, for several evenings 

 together, just at a quarter past five in the afternoon, they all 

 scudded away in great haste towards the south-east, and 

 darted down among the low shrubs above the cottages at the 



