Oath of Silence Protects Amazing 500-Year-Old Diving Bell Used to Visit Sunken Roman Vessels
A vow of silence has protected the mystery behind an ingenious invention for nearly 500 years. The secrets behind Guglielmo de Lorena’s amazing diving bell, a technical marvel, would have remained an engineering puzzle if not for the attentions of a curious maritime researcher.
The article “Guglielmo’s Secret: The Enigma of the First Diving Bell Used in underwater Archaeology” as written by researcher Dr. Josheph Eliav and published in the International Journal for the History of Engineering & Technology , hypothesizes a solution to the longstanding mystery of how two men in the 1500s were able to remain deep underwater for hours at a time in order to examine ancient wrecks and return to the surface with amazing artifacts.
Italian Guglielmo de Lorena is credited with inventing the first one-man diving bell. It boasted a revolutionary air-supply mechanism which would exchange the air inside while maintaining pressure, allowing the diver to remain underwater for hours.
In July 1535, set on exploring a sunken Roman vessel in Lake Nemi, Guglielmo de Lorna and partner Francesco de Marchi used the invention to examine and document sunken barges which had lain at the bottom of Lake Nemi. These wooden barges had once reputedly served as floating platforms for infamous Roman emperor Caligula in the first century A.D.
The remains of the hull of one of the two ships recovered from Lake Nemi. Workers in the foreground give an indication of scale. Wikimedia Commons
A Nemi ship, an ancient Roman ship, as reconstructed. Wikimedia Commons
Diving bells have a long maritime history as one of the earliest types of equipment used for underwater exploration and work. Such technologies were described by Greek Philosopher Aristotle in the fourth century B.C.
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Although diving techniques have been used since ancient times in the quest for pearls, sponges and food, and visionaries like Leonardo da Vinci had proposed snorkels and underwater breathing devices earlier to explore the mysteries of the deep, Eliav writes that Guglielmo’s diving bell is said to be the first actual use of an underwater breathing apparatus in aquatic archaeology.
Dr. Joseph Eliav, research fellow of the Leon Recanati Institute of Maritime Studies , University of Haifa, Israel, writes:
[Guglielmo’s] was not the first attempt to salvage a sunken ship but it was the first undertaken for the sole purpose of learning about it. Guglielmo de Lorena and Francesco de Marchi deserve credit for being the first to practice archaeology underwater using a breathing apparatus. Diving bells had been used before for military purposes and for salvage; even Alexander the Great allegedly used one in the siege of Tyre. Early Modern authors, including Leonardo da Vinci, describe various devices for air supply to submerged divers, mainly masks or helmets with long snorkels, but this was the first actual use of an underwater breathing apparatus in aquatic archaeology.
16th century Islamic painting of Alexander the Great lowered in a glass diving bell. Public Domain
Their ability to remain underwater for these unprecedented lengths of time was a first.
Fancesco de Marchi kept detailed records of their dives, but swore an oath of silence on the all-important mechanism that allowed the air to be refreshed in the bell. He did describe the rest of the bell, allowing modern researchers a glimpse into the world of the 16 th century marine archaeologist.
The journal article relates points noted by de Marchi. He wrote that that the bell was a round barrel of oak wood secured with iron hoops, which on land was too heavy for a single man to carry. The outside was greased and sealed like a ship. Divers were able to look out of the bell through a palm-sized piece of crystal which was set into the sidewall. Straps were used to secure the barrel around the upper body, but hands were free to reach out below the rim to tie ropes, or operate hammers or other tools.
“From the waist up, it felt as if one was in a hot oven but from the elbows down one felt a great cold,” described de Marchi.
Theorized mechanism of air supply. Credit: The Newcomen Society for the Study of the History of Engineering & Technology 2015
So convenient to these early researchers was the bell, that not only were the men able to spend great lengths of time submerged and breathing freely, but they were also able to bring luxuries like food into the bell to be eaten while diving.
De Marchi lamented, “I brought with me, to eat, four ounces of bread and one of cheese. The bread, being black and not fresh, crumbled and many fish rushed at me to eat the crumbs. The worst was that, since I did not wear pants, they bit me in that part that anyone can imagine.”
In his article, Dr. Eliav analyzes the historical texts and provides evidence for what he believes to be the exhaust valve solution to Guglielmo de Lorena’s invention. Ultimately, the diving bell was able to expel exhaled air, and allow for the introduction of fresh air, all while maintaining pressure enough to keep the interior water level from rising. Eliav suggests Guglielmo came up with the elegant solution 200 years before the officially recognized inventor of such a system – Edmund Halley in 1714.
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From these early steps in underwater archaeological research, the industry now employs high-tech submersible exo-suits to explore previously inaccessible wrecks, such as the Antikythera wreck, located off the island of Antikythera in the Aegean Sea. The famous underwater archaeological site was thrown into the spotlight in 1900 when researchers discovered an incredible mechanical device, now known as the Antikythera mechanism.
Over the decades, divers have attempted to investigate the ancient shipwreck, but dangerous conditions caused by the extreme depth of the submerged vessel prevented researchers exploring the site fully. However, a newly developed exo-suit, which allows divers to descend to 300 meters for hours at a time without the need for decompressing upon returning to the surface, has now allowed marine archaeologists to finally return to the famous wreck.
WHOI Diving Safety Officer Edward O'Brien "spacewalks" in the Exosuit, suspended from the Hellenic Navy vessel THETIS during the 2014 Return to Antikythera project. Credit: Brett Seymour / Return to Antikythera 2014 .
Maritime research and underwater archaeology continues to this day, built upon the legacy of the many individuals who came before, creating their own ingenious methods of exploring the deep and locating hidden treasures.
Featured Image: An early diving bell used by 16th Century divers during salvage operations. The book this came from is a text on ship salvage and includes diving information. Circa 1562. Public Domain
Journal Cited: International Journal for the History of Engineering & Technology 01/2015; 85(1):60-69. DOI: 10.1179/1758120614Z.00000000060
By Liz Leafloor
The oath was to protect the revolutionary valve tech: “Their ability to remain underwater for these unprecedented lengths of time was a first. Fancesco de Marchi kept detailed records of their dives, but swore an oath of silence on the all-important mechanism that allowed the air to be refreshed in the bell.”
Modern investigators feel that they’ve pieced together the design from historical records, solving the ancient mystery.
I must have missed something in the article. What oath of silence and how was it broken?
It was a good invention that should have been put into use much faster. There is alot of unexplored things under the coastlines of the world..
I read the article thoroughly and with anticipation that the (intital drawing) diving bell will be explained in detail (how it works).
What a disappointment and I thought that this was the purpose of the article.