184 THE NATURAL HISTORY OF SELBORNE. 
again into the ground, and the swallows were seen no more 
until the roth of April, when, the rigor 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 con- 
clude that they had taken their last farewell; but then it may 
be seen in my diaries also that considerable flocks have dis- 
covered themselves again in the first week of November, and 
often on the fourth 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 November, 
more than twenty house-martins, which, in appearance, had 
all departed about the 7th 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 dis- 
trict. The preceding day was wet and blustering, but the 4th 
was dark, and mild, and soft, the wind at southwest, and the 
thermometer at 5814°; 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 its 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 “/zruwndines do never leave this island at 
all, but partake of the same benumbed state; for we cannot 
suppose, that after a month’s absence, house-martins can return 
from southern regions to appear for one morning in November, 
