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Diving Past and Present
People have been diving for
thousands of years in search of pearls, valuable sponges, fish and
other foods. Pearls have been gathered in the Arabian Gulf
since 3000 B. C. Early divers wore tortoise-shell nose clips
to keep water out of their nostrils. The earliest known divers had no diving
equipment, but could dive to 60 - 100 feet (20-30 m) while holding
their breath. As time passed the development of
diving aids evolved. Leonardo da Vinci (1452-1519), Italian artist
and inventor, designed a device for breathing underwater.
In 1690 the astronomer
Edmund Halley invented the first diving bell. Divers sat in
a wooden cask (barrel) with an open bottom. As it was lowered, the
air inside was squashed by the rising water, so extra air needed
to be pumped in from wooden barrels. Divers were even able
to walk outside of the bell wearing small barrels over their
heads.
In 1837 the first diving
suit was developed by a German man named Augustus Siebe. His
invention was called the "Helmet Suit." This
watertight rubber suit had a heavy copper helmet which kept the
diver on the seabed. Air was pumped down from the surface of
the water. Divers were able to work at over 300 feet (90 m)
while wearing this.
In 1865, Benoit Rouquayrol
and Auguste Danayrouze invented a diving set that did not need an
air hose from the surface. The air needed by the diver was
carried in a canister and fed through a valve in the
helmet.
Many early divers suffered
from a strange, and often fatal disease known as decompression
sickness, or the bends. If divers come to the surface too
fast, the decrease in pressure makes the nitrogen gas in their
blood form bubbles. These bubbles block the blood's
flow. Divers with the bends must go into decompression
chambers with high air pressure, to make the gas dissolve.
Today, dive computers can work out the safest ascent speed.
Modern SCUBA (Self-Contained
Underwater Breathing Apparatus) gives divers great freedom under
the water. The Aqua-Lung, the first breathing device which
allowed people to dive independently, was invented in the
1940's. Jacques Cousteau and Frederic Dumas are responsible
for developing the demand valve. This valve gives air to
divers when they breathe in (rather than all the time, which
wastes air.)
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