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The History of the Diving Bellby Arthur J. Bachrach, Ph.D.Reproduced from Historical Diving Times Issue 21 (Spring 1998) |
The beginnings of the diving bell are undoubtedly in the use of primitive but functional devices, containers such as buckets or cauldrons. These devices trapped air when inverted and were placed over the diver's head before he entered the water. Aristotle was an early observer of such practices. In the 4th century BC he wrote, "...they enable the divers to respire equally well by letting down a cauldron, for this does not fill with water, but retains the air, for it is forced straight down into the water." Many centuries later, in 1771, an unknown author, in an article on the diving bell in the first edition of the Encyclopaedia Britannica, offered an explanation of trapped air as it worked in a diving bell, with complications beyond those encountered in the use of a simple inverted container. "The air in a diving bell is compressed by the weight of the atmosphere before the bell is let down into the water. But when it has sunk 35 feet below the surface, the air contained in it is compressed by the weight of the atmosphere as before, and by the weight of 35 feet of water besides, which is equivalent to another atmosphere. Therefore the compressing force at this depth is doubled, and consequently the air in the bell will then be twice as dense as the compressed air that we breathe. As much air, likewise, as just fills the bell, when it is a the surface of the water, will, at the depth of 35 feet, fill only half of it, for as the compressing force is doubled, the same quantity of air will be reduced to half its usual dimensions. For this reason, the water would rise into the bell through the base or bottom of it, which is always open, and would fill the other half of it if there was not a contrivance for bringing down additional air enough to force out this water, and to keep the whole capacity of the bell full of air." (Vol. 3, 1771) He goes on to describe a device for bringing down fresh air and also to comment upon the problem of the air being heated. Other observers have remarked that the heating of the air, by breathing and by pressure, posed a problem for bell divers. Aristotle, in his work Problemata, tells the tale of Alexander the Great. At the siege of Tyre, in 332 BC, he was lowered in a diving bell, also noted in the Roman 12th century Alexandriad which, in iambic lines of six feet or twelve syllables of verse (hence the term Alexandrine) relates the tale that Alexander had built "a very fine barrel made entirely of white glass" which was towed out to sea and lowered into the water. In the Alexandriad version, two companions accompanied Alexander and all were stunned by what they saw by the bright lights emanating from the diving machine. Alexander is quoted as observing, from what he had seen underwater, that "...the world is damned and lost. The large and powerful fish devour the small fry." Yet another story regarding Alexander's underwater adventures was published in 1886 in France. This book on Alexander reported that, at the age of 11, Alexander entered a glass case, reinforced by metal bands and had himself lowered into the sea by a chain over 600 feet long. Such accounts, while fanciful, demonstrate the long-standing interest in undersea exploration. Searle points out a fact that makes the event even more fanciful, that in the era stated as the date of the plunge, the metallurgy of the time was so primitive that any chain links forged would have been too weak to sustain such a weight. Some centuries later, circa 1250, the Franciscan monk, Roger Bacon, in his work, De Mirabili, speaks of devices which can be "made by means of which men could walk on the bed of the ocean without harm to their bodies. Alexander used such a device in order to discover the secrets of the sea." Lord Bacon, Francis Bacon, in his classic philosophical work, Novum Organum (1620) describes an "...apparatus which has sometimes been used to work on submerged vessels, and which enables the diver, by returning to it from time to time to breathe, to remain for a very long time under water." He goes on to detail its construction: a hollow metal vessel lowered into the sea, carrying a supply of air in a manner similar to the diving bell and what, in modern diving would be called a "telephone booth" where divers could pop in for a breath of fresh air. Francis Bacon's hollow metal vessel lowered into the sea was similar in concept to the type of diving bell invented by Lorini, reported in his book on fortifications in 1597. This device was a square wooden contraption, bound with iron bands, the diver sitting on a stone for ballast, with glass ports. Lorini viewed the advantages of this device as providing the means for recovering pieces of artillery from the sea, fastening cables and the like. "And, " he observed, "apart from this they are very useful for gathering coral." Perhaps the earliest accurate report of a diving bell successfully used is that of Lorena's device, described in a work published in 1599 by de Marchi. Lorena's bell covered the top half of the diver's body, had a glass port for observation, and the operator could extend his hands from under the rim. It was used in an attempt to recover Caligula's pleasure galleys in Italy's Lake Nemi. A few years later, in 1538, a German writer whose name is variously spelled "Tassinier," Taisnier" and "Tasinier" and who worked for the Emperor Charles V, accompanied the Emperor to Toledo where they witnessed, along with ten thousand other spectators, two Greek divers in a demonstration of a diving bell. "They suspended a large Kettle to ropes, having its mouth inverted, and planks fixed within it to sit upon; and in this situation, taking with them a lighted candle, they decended [sic] to the bottom. The Kettle was equipoised by means of lead fixed round its mouth, and by the weight of which it sunk. When it was drawn up, to the great astonishment of all present, the men were not wet, nor was the candle extinguished!" Davis suggests the Greeks were jongleurs, trick performers used to engaging in acts of skill and daring, and, furthermore, the depth reached in the River Tagus could not have been significant. The year 1551 witnessed the diving machine invented by Nicholas Tartaglia which Davis describes as consisting of "...a wooden frame like that of a gigantic hour glass, to which a heavy weight was attached by a rope. A man standing in the frame, with his head enclosed in a large glass ball, open only at the bottom, "wound himself down to the sea floor by turning a windlass on which the rope was coiled. Davis describes the device as "impracticable" and observes that it was not very clear just what the diver could do when he actually reached the bottom. A few years ago, Al Giddings had a craftsman construct replicas of historical diving equipment, including a working model of Tartaglia's diving bell. Pete Romano demonstrated that he could descend in Tartaglia's device to a depth of 30 feet, recover an object on the seabed and return to the bell for a breath of air. Although it worked, Davis was probably correct in suggesting the device was "impracticable," allowing the diver a scant few minutes working under water. In 1616, the German inventor Kessler introduced his diving bell with glass ports and a ballast weight for stability, but could have proven hazardous. Many historians have observed that if the diver took one false step, the bell would probably capsize, drowning its occupant. In the mid-1600s two interesting references to the use of diving bells appear in the literature of diving. One is a bell reported as being used during the voyages of a Spanish explorer, Don Francisco de Ortega in California (Mexico's Baja California) during the years 1632-1636. Unfortunately, no illustration has been located of an invention attributed to Ortega, which he is said to have employed during his explorations. This was a diving bell described by the ship's scribe as being made of "wood and lead... so that one or two persons can go down in it to whatever depth without danger of being drowned, even though they remain under the water ten or twelve days." This is a tantalising reference to what appears a most improbable device, unless de Ortega discovered saturation diving. It is impossible to confirm the report. A more successful diving bell is the bell invented by Edward Bendall, a freeman of the colony in Massachusetts. In the Journal of Governor John Winthrop, an entry dated 27 July 1640 reads: "Being the second day of the week, the Mary Rose, a ship of Bristol, of about 200 tons, her master one Captain Davis, lying before Charlton [Charlestown], was blown in pieces with her own powder..." with great loss of life to the crew. The General Court contracted with Bendall to clear the harbour of the wreck. The Court gave Bendall "...the liberty to make use of any of the cables, and other things belonging to the worke, as he needeth, allowing hurt of them" and Bendall designed and built two wooden diving bells, "two great tubs, bigger than a butt, very tight, and open on one end, upon which there were hanged so many weights as would sink it to the ground (600 wt)" Bendall used the bells to make fast the cables, to recover the remaining cargo and ordnance of the sunken galleon. One giant cannon was brought to the surface and deposited in the lighter moored alongside. The cannon created a good deal of curiosity because it was rumoured that treasures had been secreted in the barrels of the guns. Bendall, who had heard the rumours, did a casual search of each cannon, removing, from one gun a large padding of rope yarn which seemed strangely heavy. He thought that the weight had come from being waterlogged. Bendall could not credit the idea that the ship's masters would put valuable gold and silver coins inside a cannon's mouth. Then one day he decided to test the cannon and rammed the rope yarn inside to use a wad for firing. At high tide the cannon was fired and a large array of coins exploded into the air, settling in the harbour waters. The following day, at low tide, people walking the strand along the sandy beach were startled to see silver and gold coins gleaming in the sand and, of course, made free with the treasure. Bendall petitioned the General Court for a patent for his diving bell, probably the first in the Colonies, but was denied. [See Snow, Fardell] The Portuguese galleon Florencia was sunk, in 1588, as part of the Spanish Armada expedition, resting in Tobermory Bay, Mull. In 1665 an expedition used a diving bell to recover cannon, a feat discussed by George Sinclair, a Professor at Glasgow University, who, in 1669, published a book in which he described the bell used, attempting a rationale for the physics, physiology and engineering of a diving bell. In 1678 a French physician, Dr. Panthot, described in detail the famous salvage of the ships sunk on the reefs off Catalonia, Spain, in the port of Cadaques (then called Capdaques). Two boats carrying a transverse beam between them supported the bell, which was made of wood. It was around thirteen feet high by nine feet across and the diver was seated on a crossbar in the middle of the bell. One of the two Moorish divers was able to work the bell for periods as long as two hours, but the other could not stand the heat generated in the bell, and thus was limited to around one hour of work. The divers' reward was to keep as many coins as they could hold in their hand and mouth. Around the same time, in 1680, a report by the physiologist Giovanni Borelli, published posthumously, proposed a diving bell which was small and quite impractical. In an analysis by the mathematician, Bernoulli, the design was severely criticised as unworkable. In the figure, next to the diving bell Borelli proposed, is a breathing tube, not unlike that of Lorini's, which Borelli preferred to the concept of a diving bell. It is likely that the user of the breathing tube would have been asphyxiated. One of the more famous and successful applications of what must have been a primitive diving bell of the inverted container type, is that of William Phipps. He was an American born in 1650 who convinced Charles II to provide him support to salvage a treasure lost when a Spanish ship sank of the coast of San Domingo. His first efforts, in 1683, proved unsuccessful. He returned to England to raise money for another expedition, was refused by James II, but received support from the Duke of Albemarle. He returned to the West Indies in 1687 and his efforts produced 200,000 pounds sterling, earned him a knighthood and eventually made him High Sheriff of New England. In 1689, the French physicist Denis Papin proposed what appears to be the first plan to provide air to the diving bell, under pressure, from the surface. Papin's proposal, never realised in an actual working model, was to use force pumps or bellows to maintain a constant pressure within the bell. As we will see, the use of barrels of air for replenishment, used by Halley, continued for over a century until Smeaton introduced a successful force pump in 1788. It is generally agreed that the diving bell invented by Edmund Halley is undoubtedly the forerunner of the modern diving bell. In 1690, Halley designed and built, of wood, a bell in the form of a truncated cone, with the larger end (diameter 5 feet) being open and the top (3 feet) closed. In Smith's words, "It was poised with lead, and so suspended that it might sink full of air, with its open part downward, and has as nearly as possible in a situation parallel to the horizon-so as to close with the surface of the water all at once." There was a clear glass port on the top for light and vision as well as a cock to let out the heated, breathed air. About three feet below the open end of the bell was a stage that was suspended by three ropes, each of which was weighted with " about one Hundred Weight, to keep it steddy. [sic]" The air was replenished by the use of two barrels, each containing thirty-six gallons. They were weighted with lead to sink them, and had a bunghole in the lower part to let in water as the air condensed on the descent and to let it out when the barrel was drawn up full. Another bunghole was placed in the top of the barrel to which a leather hose was attached. This pipe or hose was prepared with beeswax and oil and was weighted to hang below the bottom bunghole so that no air could escape unless the lower part of the barrel was first raised. When the hose was moved under the bell, a diver could grab the end of the hose and lift it into the bell. The pressure of the water forced the air contained into the barrel through the bottom bunghole up into the bell. Alternating the barrels, which were refilled on the surface, the barrels could be lowered and raised via tackles, providing a continuous supply of fresh air. Using this technique, Halley stated that he and four other divers remained on the bottom for an hour-and-a-half at a depth of nine or ten fathoms. Halley's method of replenishing the air was simple and effective and, in his essay The Art of Living under water he wondered why someone had not thought of it before. In fact, George Sinclair in his 1669 work had proposed sending air down to the bell in very much the same manner. Halley suggested "an additional contrivance" for the bell. He proposed a means "...for the diver to go out of our engine to a good distance from it, the air being conveyed to him in a continuous stream by small, flexible pipes, which pipes may also serve as a clew to direct him back again when he would return to the bell." These divers would be fitted with a small, auxiliary bell over their upper body, fitted to the pipes from the bell. Thus was born the first diver lockout system. In his discussion of Halley's bell, Davis suggests that Halley may have been aware of Papin's proposal to use force pumps or bellows to provide a continuous supply of air to the bell, but that Halley feared that, should he employ the device, Papin might accuse him of plaigarism. It is indeed probable that Halley was aware of Papin's idea, inasmuch as Papin, a French physicist was a Fellow of The Royal Society, of which Halley was then Secretary. Papin had written a brief essay, published in 1691, entitled How to Preserve a Flame Under Water in which he discussed a watertight lantern in which a candle burned to assist in night fishing. In this essay he went on to say that this problem of a watertight container to which air needed to be conveyed led him to a consideration of improving the diving bell. He proposed a system with leather bellows fitted with valves and pipes through which the air could be forced. As he writes," Should these leather bellows not prove strong enough to set up the extra pressure required at great depths, the difficulty could always be got over by the use of pressure-pumps." This appears to be the first time the use of forced air to replenish the bell was proposed but, as we noted above, Halley did not employ the technique and the use of barrels for replenishment continued for a over a century until Smeaton, in 1788, designed the first diving bell using forcing-pumps. Mårten Triewald was a Swedish Army officer and architect to the king of Sweden, who in his report on The Art Of Living Under Water, published in Stockholm in 1734, acknowledges his debt to his "friend and patron," "the learned and ingenious Englishman Doctor Edmund Halley." Triewald indeed took the name of his report, submitted to the "Supreme King Friedrich, King Of the Swedes, the Goths and the Wends, and Ruler Of Hesse" from the 1716 paper published by Halley in Philosophical Transactions. Triewald offers a most interesting comment in his report which suggests very strongly that he may have been aware of Papin's proposal to send air down from the surface. "All those inventions based on supplying air in its natural air [sic] through tubes from the surface have no valid foundation and are generally devised by those totally ignorant of what they are dealing with." So he continued Halley's system of replenishing air via alternating barrels. Triewald's bell, smaller and lighter than Halley's was made of copper rather than wood and was lined with tin. Lead weights were attached to the rim. Only one diver could use it at a time. Three strong iron chains attached to the rim suspended a plate on which the diver could stand (in a manner similar to the one attributed to Sturmius) and have his head just above the water level for air intake. Triewald also placed a spiral pipe fixed at the side of the bell through which the diver could breathe, no matter what his position. Following the design Halley used in his bell, a Scots inventor, Charles Spalding built a bell in 1775 which could be controlled by its occupants by means of a tackle, raising or lowering a central weight. Made of wood, the bell was successful. It relied again on Halley's barrel system of air replenishment. In 1788 the first modern diving bell was constructed by the noted engineer the British John Smeaton. Best known for his construction of the third Eddystone lighthouse, Smeaton used, for the first time, a force pump and tube arrangement like that proposed by Papin over a century before. The bell had a force pump mounted on its roof, meaning that it could be totally submerged. It was used for repairs on the foundation of Hexham Bridge. Smeaton designed the bell to be a rectangular box of cast iron and referred to it as the "diving chest," about 4 1/2' high x 4 1/2'long x 3' feet wide, accommodating two divers. Davis makes the cogent point that using forced air allowed designers to use a rectangular form instead of the "truncated cone" type of bell. With the former, having to rely on replenished air from a barrel, the advantage of the bell shape was that "... the deeper it went, the slower, proportionately, the water rose in it, owing to the ever lessening diameter of the water-plane area." With air delivered under pressure from above, the shape is immaterial and led to the box design incorporated into later diving bells. One ingenious engineering element Smeaton built into his diving chest was a reservoir designed to ensure that any sudden failure of the force pump would not result in a shut-off of air. He also incorporated a non-return valve to prevent air being sucked out through the tube. Another great British engineer, James Rennie, designed a bell for use in Ramsgate Harbour. The year was 1812. The bell, or "chest" inasmuch it was rectangular in a manner similar to that of Smeaton's, was made of cast iron, again with a force pump at the surface, operated by four men; unlike the Smeaton chest, the force pump was topside and not on the roof of the bell. It weighed 4,200 lbs, and had twelve convex lenses to admit light. A hole in the roof housed a leather hose, long enough to permit reaching depth, which was attached to the force pump. As with Smeaton's bell, Rennie also had a non-return valve in the form of a leather piece screwed to the air hole. Air entered in the spaces between the spaces between the screws and was prevented from returning through the hose. The leather "non-return valve" also kept water from entering the bell should the hose rupture. Rennie's diving bell played a central role in the repair of the collapsed Thames Tunnel, which was built in 1823. Rennie's bell was featured in a famous repair operation, that of the work following the flooding of the Thames Tunnel in 1827. Marc Brunel had built the tunnel in 1823, from Rotherhithe to Wapping. Brunel was the inventor of the tunnel shield, used in the operation. The diving operations to inspect the tunnel were centered in Rotherhithe, which was about a mile up-river from Deptford, where the Deane brothers lived. Marc Brunel's son, Isambard Kingdom Brunel, who was the resident engineer on the project, borrowed Rennie's bell from the West India Company. I.K. Brunel ("The Little Giant") and his father were considered the great engineers of their time. Isambard Kingdom Brunel was also the designer of the "Great Iron Ship", the Great Eastern. John Bevan, in his book The Infernal Diver writes: "It is seen suspended by a heavy-duty chain from a massive timber davit on the bell-lighter, all borrowed from the West India Company. A diver tender is shown working hard at a lever pump whilst another, precariously perched on the davit, carefully guides the air hose clear of obstruction and snagging." The barges lying alongside are filled with hazel branches and bags of clay for the tunnel repair. As Davis notes, Rennie also provided a limited amount of freedom of movement for his bell on the bottom by "suspending it from a four-wheeled frame running on rails mounted on a platform, which in itself was mounted on another set of rails set at right angles to those which it supported." By the time Rennie had developed his bell, the open diving bell had essentially reached its modern form. Later improvements in terms of electric lighting, ballasting, communication via telephone and a better air supply made the use of the open bell more effective and safer, but the principle remained the same as in the earliest bells. Davis illustrates an early modern open diving bell, showing a diving bell on the bottom, at 70 feet, with divers working (or at least leaning on their shovels). The compressed air supplied excluded the water. The next stages of development were, in essence, twofold, one avenue leading to modern closed diving bells such as Piccard's Bathyscape and Barton and Beebe's Bathysphere in the 1950s, the other leading to the trapped air concept of the individual diving bell, the diving helmet. The diving helmet was a return, in a sense, to the inverted bucket, with hand-operated force air pumps providing a continuous air supply to the diver. Bevan's article on the invention and development of the diving helmet and dress provides a good history of the area. At times diving historians list inventions such as Lethbridge's diving barrel (described in 1715) or Rowe's 1720 barrel, the first to be patented, as variations of a diving bell, a closed device. The differences between bells and barrels are great enough to warrant treating them as separate underwater systems, with the barrel a limited, one man device, short on time and work capability. The earliest closed diving bells were used primarily as observation chambers through which divers could make visual inspection. They were raised and lowered by means of a line secured to the outside of the bell. They had a limited air supply, which was improved in later models by the addition of an air hose. The French engineer, Ernest Bazin, who was the first to use electric lighting underwater in 1864, invented one of the earliest underwater observatories, Bazin's observatory and lighting system was in use in 1872 during an expedition to salvage Spanish Galleons in Vigo Bay. As the closed diving bell developed, features such as improved air supply and diver lockout systems made the working function of the bell increasingly important. The use of the closed bell as a means of transport was also a critical development in saturation diving. An example of a bell as a Personnel Transfer Chamber (PTC) was used in the US Navy's SEALAB in which, divers compressed to the working depth in a DDC (Deck Decompression Chamber) topside are lowered in the PTC to the sea-bed and locked into the habitat, where they remain at that pressure until the mission is completed. They then re-enter the PTC, are raised to the surface support vessel, then locked into the DDC for decompression. An early example of a contemporary experimental diving bell was the Purisima, invented by Dan Wilson in the 1960s. It was a double sphere system in which the top sphere was at atmospheric pressure, allowing diving supervisors to monitor the dive at depth rather than remain topside in front of a TV monitor, while the bottom sphere contained the divers at working pressure. Wilson envisioned the top sphere as also being a means by which customer representatives could be on site as observers, but he comments, wryly, "For some reason the customers never did line up to direct their undersea operations." The hatches were situated so that the bell could also be used in a horizontal positioning. Many lessons were learned from Purisima, including proper hatch size (they were too narrow on Wilson's bell) leading to improved engineering and design. Perhaps one of the more interesting aspects of the history of the diving bell is that there is in early literature virtually no consideration of physiological factors in the diving. The engineering and physics of the bell were clearly an abiding interest but the awareness of the need for replenished air, for example, showed that there was at least a recognition of the diver's physiology. Two scientists, Antoine Lavoisier and Joseph Priestley, more or less contemporaneous (late 18th century and early 19th century) are credited with discoveries relating to oxygen and carbon dioxide. While there is still some controversy as to who exactly discovered oxygen, it is agreed that it was Lavoisier who first determined that there was a relationship between the gases oxygen and carbon dioxide, via an exchange in the lungs whereby inspired air is converted into carbon dioxide. In the diving bell, the movement of the divers would be likely to prevent any layering of gases, thereby ensuring a mix of oxygen and carbon dioxide. Vorosmarti reports a build-up of carbon dioxide in the living quarters of SEALAB II resulting from drawing curtains, illustrating the effects of a still environment. The many environments of a working diver - cold, pressure, current - can affect the physiological performance. We cannot know exactly what the gas exchange was in the various early diving bell exposures, nor can we determine with any precision what the level of work might have been, nor the levels of heat generated. We can attempt to evaluate the reported exposures of divers such as Lethbridge in his barrel, with no air replenishment, or Halley and his crew of four remaining at depth for one and a half hours with the barrel system of air supply, and try to recreate the working environment and its physiological cost. It is likely that Halley and his divers were not able to perform any significant work underwater. Sitting at rest would require much less air and generate less carbon dioxide than working. Recognising that some accounts of performance in diving bells may be a bit overblown in view of the physiology, the history of the diving bell remains a fascinating story of human inventiveness, engineering skill, courage and exploration. In the literature of diving bells there is an account of two experiences related by S.W. Smith, Superintendent of Plymouth Dockyard, who, in his book tells of the many "persons of rank" who visited the Yard and who experienced the diving bell used in public works. Among them was His Serene Highness the ArchDuke Maximilian, who descended to the bottom in 1818. Smith recounts that His Highness on the bottom selected a stone and "...ascended with it, intending to preserve it as a memorial of his submarine excursion, with which he expressed himself highly delighted." The other experience related by Smith is a charming one in which a Lieutenant Colonel Fairman, with Major and Mrs. Morris descended in the bell. Smith writes," When at the bottom of the sea the lady wrote three sides of a sheet of paper, and folded it into a letter to send to her father, which she concluded with the following lines: "From a belle, my dear father, you've oft had a line, But not from a BELL under water; Just now I can only assure you I'm thine, Your diving, affectionate daughter." I am grateful to CAPT. W.F. Searle (USN, Ret.) and to Drs. James Vorosmarti and Michael Rosco for comments and suggestions. REFERENCES 1. Searle, W.F.Personal communication. |