NATURAL HISTORY OF SELBOllNE. 
53 
The vast rains ceased with us much about the same time as with 
you, and since we have had delicate weather. Mr. Barker, who has | 
measured the rain for more than thirty years, saj^s, in a late letter, that, \ 
more has fallen this year than in any he ever attended to ; though 
from July 1763 to January 1764, more fell than in any seven months 
of this year. 
LETTEE XXJIL 
TO THE SAME. 
SelbornSj Feb. 2St7i, 17m. 
Dear Sir, — It is not improbable that the Guernsey lizard and our 
green lizards may be specifically the same ; all that I know is, that, 
when some years ago many Guernsey lizards were turned loose in 
Pembroke college garden, in the University of Oxford, they lived a 
great while, and seemed to enjoy themselves very well, but never bred. 
Whether this circumstance will prove anything either way I shall not 
pretend to say. 
I return you thanks for your account of Cressi Hall ; but recollect, 
not without regret, that in June 1746 I was visiting for a week together 
at Spalding, without ever being told that such a curiosity was just 
at hand. Pray send me word in your next what sort of tree it is that 
contains such a quantity of herons' nests ; and whether the heronry 
consists of a whole grove of wood, or only of a few trees. 
It gave me satisfaction to find we accorded so well about the 
caprimulgm; all I contended for was to prove that it often chatters 
sitting as well as flying ; and therefore the noise was voluntary, and 
from organic impulse, and not from the resistance of the air against the 
hollow of its mouth and throat. 
If ever I saw anything like actual migration, it was last Michaelmas 
Day. I was travelling, and out early in the morning ; at first there 
was a vast fog ; but, by the time that I was got seven or eight miles 
from home towards the coast, the sun broke out into a delicate warm 
day. We were then on a large heath or common, and I could discern, 
as the mist began to break away, great numbers of swallows {7iirundi7ies 
Tusticce) clustering on the stunted shrubs and bushes, as if they had 
roosted there all night. As soon as .the air became clear and pleasant 
they all were on the wing at once ; and, by a placid and easy flight, 
proceeded on southward towards the sea ; after this I did not see any 
more flocks, only now and then a straggler. 
I cannot agree with those persons that assert that the swallow kind 
disappear some and some gradually, as they come, for the bulk of them 
seem to withdraw at once ; only some stragglers stay behind a long 
while, and do never, there is the greatest reason to believe, leave this 
island. Swallows seem to lay themselves up, and to come forth in a 
warm day, as bats do continually of a warm evening, after they have 
disappeared for weeks. For a very respectable gentleman assured me 
that, as he was walking with some friends under Merton Wall on a 
remarkably hot noon, either in the last week in December or the first 
