UNIVALVES. 189 
mercial nations, by occasioning a perpetual demand 
for oak, pitch, and fir. And as these, apparently, 
pernicious insects are continually at work at Amster- 
dam, for the advantage of Stockholm and Archangel, 
so the labours of others in the north are equally 
profitable to the Hollanders, by promoting the con- 
sumption of their salt, spices, and grocery, which 
are annually exported in large quantities, either for 
the purpose of seasoning and preserving the provi- 
sions of their northern neighbours, or to cure the 
fish, which they use instead of bread. 
Cease then, my friend, to regard those creatures 
as decidedly obnoxious, the use of which you do 
not readily perceive. The Yeredo is, apparently, an 
insignificant reptile, nay, more than insignificant ; 
it appears, on a slight acquaintance, to be injurious: 
yet the Creator has assigned it an important station 
among his works. The evil which it produces, is 
readily obviated by a little care and contrivance; but 
the good which it is appointed to effect, is incalcu- 
lably great in the mighty scale of universal nature, 
Adieu. 
