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4th
c. BC
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The first depictions of
underwater devices are pointed out by Aristotle who mentioned that “…one
can allow divers to breathe by lowering a bronze tank into the water. Naturally
the container is not filled with water but air, which constantly assists
the submerged man”. This device represented a jar, turned upside down,
in which the diver thrust his head. During his descent to the sea floor,
he breathed the air that remained inside the jar. Actually, this is the
prototype of the true diving bell. |
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325 BC
|
 Alexander
the Great and his comrade Nearch (the commander of the fleet) managed to
go under surface to a depth of 25 meters with the aid of a huge diving
bell. It consisted of colorless glass to help the diver see through it. |
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Early
Centuries
AD
|
 A
typical diving bell: leather bags to refresh the air were dropped by the
surface;
The diver went out from
the diving bell with his breath held, to do some work under water. After
he was out of breath, instead of ascending to the surface, he returned
to the bell where he inhaled fresh air;
Stones were attached to
the brim of the wooden barrel to help the bell sink;
When the air became unbreathable,
the bell was taken to the surface for ventilation; |
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Middle
Ages
|
 In
this epoch, sea was considered a mysterious and threatening power, a dangerous
and unknown world. The tall stories told by monks and priests aroused superstitious
fear which became the main reason for less interest towards diving. Look
how people from this period imagined diving. |
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Renaissance
|
 This
was an incredible period in terms of revival and development of diving.
Many experiments were conducted and these attempts were not futile. Among
the most famous personalities, engaged with diving inventions, were Halley,
Sturm, Borelli. In his book “Codex Atlanticus” Leonardo Da Vinci describes
the forerunners of the fins, snorkel and breathing apparatus. He also designed
a diving helmet of leather. It had spikes against monsters in the oceans
and a breathing tube leading to the surface. In this period Torricelli,
Bernoulli and Pascal set the basis of physics, hydrostatics and aerostatics
which led to important conclusions concerning diving. |
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1535
|
 The
first diving bell was invented. Guglielmo de Lorena made a device that
can be considered a true diving bell. This apparatus rested on diver’s
shoulders and had much of its weight supported by slings. This bell provided
enough air for the diver to breathe. |
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1583
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In the presence of Charles
the Fifth and other 10,000 curious citizens, two men dove in the Tagus
River (Toledo) using a large bronze diving bell and stayed 20 minutes on
the sea floor. |
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16–17th c.
|
Galilei
and Denis Papin adapted to the diving bell an air pump through which fresh
air can be transported to the people under water. The bell had the shape
of a frustum of a cone in which the main elements are the valves. |
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1619
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Sir Edmund Halley patented
a bell which looked like the above mentioned bell. According to some sources
of information, Halley was aware of Galilei and Papin’s plan and made a
device following their idea. The inventor is debatable but there is no
doubt about the appearance of the bell.
Thick glass to let light
in;
Coated with lead sheets;
Barrel with replenished
air
It was equipped with three
auxiliary ballast weights;
Individual bells, fastened
to diver’s shoulders and connected with a pipe to the main bell, that allowed
him to walk away for unlimited time without returning for rebreathing. |
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1667
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Using
the bell, developed by Galilei and Papin, William Phipps managed to salvage
a huge treasure from a wrecked ship near the coasts of Espanola. The same
year, Albrecht von Treileben brought out 53 weapons found 40 meters in
depth on a sunken vessel. |
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1716
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Edmund Halley invented two
types of bells: a wooden bell, assisted with two barrels with fresh air
that reached the bell with a tube, and a lead bell. The latter had seats
for several divers. Air was supplied in the same way. Halley and other
four men stayed submerged with this device at a depth of 18 meters for
90 minutes. The only problem they suffered from was awful pain in the ears.
They didn’t still know anything about water pressure and its effect on
human organism. |
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1788
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John Smeaton
(American) improved the diving bell by adapting a hand-operated pump to
provide fresh compressed air. The main characteristic is that the valve
is non-return – it does not allow air to return when pumping stops. In
the next years, Smeaton’s device was used in all major harbors for salvaging
ships. |
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18th
c.
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Only at the end of the 18-th
century was the diving bell fully studied and improved. Its use is no more
a technical problem. The main disadvantage of the diving bell is that it
should be pulled up to the surface for the workers to be replaced which
is a time- and energy-consuming process. |
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