a
little history of sound
- Leonard
da Vinci observed, "If you cause your ship to stop and
place the head of a long tube in the water and place the outer
extremity to your ear, you will hear ships at a great distance
from you."
- Sir Isaac
Newton in Philosophia Naturalis Principia Mathematica
was the first to publish a mathematical theory of the propagation
of sound in 1687.
- In 1826
Daniel Colladon was the first to accurately measure the speed
of sound in water. He used da Vinci's idea and measured the time
it took for the sound of a submerged bell to travel across Lake
Geneva.
- In 1877
and 1878 John William Strutt published his two volume series
The Theory of Sound and thus marked the beginning of the
modern study of acoustics. He was the first to write down a mathematical
equation for the description of a sound wave.
- Throughout
history very simple forms of echolocation have been used by seafarers.
The Phoenicians for example gauged distances to land in the fog
by making loud sounds and listening for echoes.
- In more
modern times, the Titanic tragedy inspired L. R. Richardson to
patent for echoranging with airborne sound and its equivalent
for use under water. World War I and World War II had a profound
effect on the development of echo rangers (SONAR). By the out
break of the second World War all US naval ships were equipped
with sonar that could pick up the noise of a submarine from thousand
of yards away. Harvey C. Hayes, a naval engineer, encouraged
the US Navy to play a role in oceanography during peacetime,
a tradition which continues today. The resources that the navy
provided opened up a new world for oceanography.
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