OF S E L B 0 R N 
-had taken their laft farewell : but then it may be feen in my diaries 
alfo that confidcrable flocks have difcovered themfelves again in 
the firft week of November, and often on the fourth day of that 
month only /or one cfay; and that net as if they were in aftual 
migration, but playing about at their Icifure and feeding calmly, 
as if no enterprize of moment at all agitated their fplrits. And 
this was the cafe in the beginning of this very month ; for, on the 
fourth of November, more than twenty houfe-martins, which, in 
appearance, had all departed about the fcventh of Oclober, were 
feen again, for thd,t one moriiifig only, fporting between my fields and 
the Ha/jorr, and feafting on infects which fwarmed in that flieltered 
diftricl. The preceding day was wet and bluftering, but the fourth 
was dark and mild, and foft, the wind at fouth-weft, and the ther- 
mometer at 58'-! ; a pitch not common at that feafon of the year. 
Moreover, it may no tbe amifs 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 thefe circumftanccs laid together, it is obvious that 
torpid infects, reptiles, and quadrupeds, are awakened from their 
profoundeft flumbers by a little untimely warmth ; and therefore 
that nothing fo much promotes this death-like ftupor as a defeft 
of heat. And farther, it is reafonable to fuppofe that two whole 
fpecies, or at leaft many individuals of thofe two fpecies, of Britijh 
hirundines, do never leave this ifland at all, but partake of the fame 
benumbed ftate : for we cannot fuppofe that, after a month's abfence, 
lioufe-martins can return from fouthern regions to appear for one 
morning in November^ or that houfe-fwallows fliould leave the dif- 
trids of Africa to enjoy, in March, the tranfient fummer of a conpk 
of days. 
I am, hc> 
F f 2 L E T T E R 
