OF SELBORNE. 239 
fogs and vapours, and even with copious dews, can 
alone advance a considerable and never- failing re- 
source. Persons that are much abroad, and travel 
early and late, such as shepherds, tuewinen. &e., 
can tell what prodigious fogs prevail in the night 
on elevated downs, even in the hottest parts of 
summer, and how much the surfaces of things are 
drenched by those swimming vapours, though to the 
senses, all the while, little moisture seems to fall. 
LETTER XXIX. 
Selborne, April 29, 1770. . 
Dear Sir,—On August the 4th, 1775, we sur- 
prised a large viper as it lay in the grass, basking 
in thé sun, with its young, fifteen in number, the 
shortest of which measured full seven inches, and 
were about the size of full-grown earthworms. 
This little fry had the true viper spirit about them, 
showing great alertness: they twisted and wriggled 
about, and set themselves up, and gaped very wide 
when touched with a stick, showing manifest tokens 
of menace and defiance, though as yet they had no 
manner of fangs that we could find, even with the 
help of our glasses. 
To a thinking mind, nothing is more wonderful 
than that early instinct which impresses young an- 
imals with the notion of the situation of their nat- 
ural weapons, and of using them properly in their 
own defence, even before those weapons subsist or 
are formed. ‘Thus a young cock will spar at his 
adversary before his spurs are grown, and a calf 
or lamb will push with their heads before their horns 
