Sonar
systems
were
first
used
on
land
during the
Boer
War
.
However
, they
proved
of
little
use
in
detecting
the
movements
of
enemy
units
. In fact,
sonar
was not again
employed
as a
military
tool
until the
invention
of
sound
detecting
equipment
in the
1920s
.
Bud Mortenson
[email redacted]
[undated]
