298 The Natural History of Se I borne 



and were very alert in many places, and particularly at 

 Chobham, in Surrey. 



But as that short warm period was succeeded as well as 

 preceded by harsh severe weather, with frequent frosts and 

 ice, and cutting winds, the insects withdrew, the tortoise 

 retired again into the ground, and the swallows were seen no 

 more until the loth of April, when, the rigour of the spring 

 abating, a softer season began to prevail. 



Again ; it appears by my journals for many years past that 

 house-martins retire, to a bird, about the beginning of October ; 

 so that a person not very observant of such matters would 

 conclude that they had taken their last farewell; but then it 

 may be seen in my diaries also that considerable flocks have 

 discovered themselves again in the first week of November, 

 and often on the 4th day of that month only for one day ; and 

 that not as if they were in actual migration, but playing about 

 at their leisure and feeding calmly, as if no enterprise of 

 moment at all agitated their spirits. And this was the case in 

 the beginning of this very month ; for on the 4th of November, 

 more than twenty house-martins, which, in appearance, had 

 all departed about the yth of October, were seen again for that 

 one morning only sporting between my fields and the Hanger, 

 and feasting on insects which swarmed in that sheltered 

 district. The preceding day was wet and blustering, but the 

 4th was dark, and mild, and soft, the wind at south-west, and 

 the thermometer at 58'^ ; a pitch not common at that season 

 of the year. Moreover, it may not be amiss to add in this 

 place, that whenever the thermometer is above 50, the bat 

 comes flitting out in every autumnal and winter month. 



From all these circumstances, laid together, it is obvious 

 that torpid insects, reptiles, and quadrupeds, are awakened 

 from their profoundest slumbers by a little untimely warmth ; 

 and therefore that nothing so much promotes this death-like 

 stupor as a defect of heat. And farther, it is reasonable to 

 suppose that two whole species, or at least many individuals 

 of those two species of British hirundines do never leave this 

 island at all, but partake of the same benumbed state ; for we 



