BORING LIFE
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to soft rocks, and calcareous rocks are always in danger
from the chemical borers, like the Date-mussel, but if
these types of rock are avoided there is no danger.
More—
_
over they work much slower and penetrate far less deeply
than do the wood borers
Cement and concrete are Seldom
attacked by them, though there are a few recorded cases
_
of these substances being bored into by Piddocks or their
relatives.
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155
to soft rocks, and calcareous rocks are always in danger
from the chemical borers, like the Date-mussel, but if
these types of rock are avoided there is no danger.
More—
_
over they work much slower and penetrate far less deeply
than do the wood borers
Cement and concrete are Seldom
attacked by them, though there are a few recorded cases
_
of these substances being bored into by Piddocks or their
relatives.
_
'
'
.
"
-
_
:
'4>
È
.
x_' . : E’
:»__‘2 ‘
!
ä(_
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,,
,3‘ ’
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,
L_
3
C3
55€“ËE ä
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.r*'—-. n, !
i“ë
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!?
.
ï _, ‘ _
___
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"
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1". ŒmZ—‘—mæü'üîäüît—zua:é
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