aiS n a t u r a l H i s t o r y
L E T T E R XXXV I.
TO T I ÏE S A M E .
D E A R S IR , Selborne, Nov. aa, 1 777,
Y o u cannot but remember that the twenty-fixth and twenty»
feventh of laft March were very hot days-; fo- fultry that every
hody complained and were, reftlefs under thofe fenfations to whioh?
they had not been reconciled- by gradual approaches.
This fudden lummer-like heat was: attended1 by many fummer
coincidences; for on thofe- two days the thermometer rofe to
fixty.-fix. in, the lh ademan y fpecies of infedts- revived and' eatn'e'
forth ; fomebees fwarmed in this neighbourhood ;,the old tortoife,-
near Lewes, in Sitffex, awakened and came forth out of it’s dormitory;
and, what-is moft to my prefent purpofe, many houfe-fwallows-
appeared and were very alert in many places, and particularly at
CoVhnrn, in Surrey-.
But as that fhort warm period1«® fucceeded'as welf as preceded
by harlh fevere weather, with frequent frofts and ice, and cutting,
winds, the infedts withdrew,, the tortoife retired again into the
ground, and the fwallows were feen no more until the tenth of
April, when, the rigour of the fpring abating, a fofter feafon began-
to prevail.
Again; it appears by my journals for many years pall that houfe-
m'artins retire, to a bird, about the beginning of October ; fo that a
perfon not very obfervant of fuch matters would conclude that they
OF S E L B O R N ^ 21$
had taken their laft farewell: but then it may be feen in my diaries
alio that confiderable flocks have difcovered themfelves again in
the firft week of November, and often on the fourth day o f that
month only for mie day, and that not as i f they were in adlual
migration, but playing about at their leifure and feeding calmly,
as if no enterprize of moment at all agitated their fpirits. 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 feventh of OSlober, were
feen again, for that one-morning- only, fporting between my fields- and
the Hanger, and: feafting on- irrfeaswhich fwarmed1 iri that fhelteTed'
diftndt. The-preceding day was \ret and bluftering, but the. fourth’
was-dark andJmild, and foft, the wind'at fouth-weft1, and the thermometer
at 58'f; a pitch not common at that feafon of the year.
Moreover, it may no tbe amils 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 circumftances laid together, it is obvious that
torpid infedts, 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 dëfètft'
o f heat. And farther, it is reafonable to fuppofe that two whole
fpecies, or at leaft many individlials of thofe two fpecies, of Eritijh
hirundines, do never leave this Mandat all, but partake of the fame
benumbed ftate: for we cannot fuppofe that, after a month’s abfence,
houfe-martins can return from fouthern regions to appear for one
morning in November, or that houfe-fwallows Ihould leave the dif-
triifts of Africa to enjoy, in Mdrch, the tranlient fummer of a couple
o f days.
I am, Sec.