Niederbayern88 schrieb:Gehst du davon aus, dass die Indianer dort Salzgewinnung betrieben haben? Oder eher diejenigen, die von Europa gekommen sind? Mit Kokosfaser Salz zu gewinnen... ich weiß nicht, wie so ein Filtrationssystem wirksam sein soll
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"A plausible case can be made that the finger or box drains are the remains of an early salt works, for the manufacture of sodium chloride or common table salt. To understand why this is so, it is useful to understand the historic context, both as regards Oak Island itself and the salt industry as it existed at the time.
The Historic Context of Oak Island
European fishermen began sailing to the rich fisheries of the Grand Banks near the Atlantic coast of Canada in the late 1400s (4). By 1580, the Grand Banks were being visited by 300 fishing boats from Europe annually, and the Grand Banks Fishery was already becoming a major industry (5). The Spanish and Portuguese fishermen tended to fish the area and sail back to Europe without landing on the Canadian Coast, but the English and French fishermen usually landed on the Canadian Coast and preserved their fish by drying and salting before returning to England and France (6). While the English shore camps for fishermen were mostly on the coast of Newfoundland, it is certainly plausible some of them would have set up fish drying and salting camps on the coast of Nova Scotia and possibly even on Oak Island itself. With the establishment of the English colonies along the Atlantic coast of what is now the USA from the early 1600s onwards, American fishermen also began sailing to the rich fishing grounds of the Canadian Atlantic coast (5).
The first known persons to definitely take up land on Oak Island were the New York fish agents John Gifford and Richard Smith who were granted three islands in Mahone Bay in 1753, including the whole of Oak Island (7). There is evidence they used Oak Island as a base for their fishing operation off the coast of Nova Scotia in the 1750s (7).
They were followed by settlers who began farming Oak Island, and the 1791 poll tax records show the presence of five households on Oak Island (8). So we know Oak Island was permanently settled by colonists from the latter part of the 1700s onwards, and it had been settled and farmed for many years when the box drains were discovered in 1849-1850.
The Historic Context of the Salt Industry
As is well-known, salt is essential for human health. By way of one random example, it is known that thousands of Napoleon’s soldiers perished during the retreat from Moscow in 1812 because their wounds would not heal owing to their lack of salt (6).
Perhaps less well-known is that until the advent of refrigeration in the late 1800s, salt was also commonly used as a preservative for food. The only truly practicable way to preserve fish caught from the rich fishing grounds of Atlantic Canada before the late 1800s was salting and/or drying the fish (often a combination of both).
The Spanish and Portuguese fishermen sailing to those fisheries from the late 1400s onwards generally preserved their catch with salt and immediately returned to Europe without making landfall on Canada. The English and French fishermen, on the other hand, usually made landfall in Canada and preserved their catches onshore by salting or drying, or a combination of the two, before returning to England and France respectively (6).
Because in our own time, salt is plentiful and cheap, we tend to forget that until the 1800s salt was generally expensive and hard to come by. Because salt was both essential and scarce, it was an obvious target for taxes, and salt was usually heavily taxed until the 1800s. The very onerous French salt tax known as the Gabelle is credited as being a primary cause of the French Revolution in 1789 (6). The British Government likewise heavily taxed salt, only repealing its salt tax in 1835 (9).
Conclusion on the Historic Context
We see that the two New York fishing agents Gifford & Smith were the first known owners of Oak Island, at a time (1753) when the fisheries of the Atlantic Coast of Canada were an important industry, and when the only practicable methods of preserving fish were salting and drying them or a combination of both. We also see that at this time salt was heavily taxed.
The Technology of Salt Manufacture
Most salt has always been made by evaporating either seawater or the brine from natural brine springs. As seawater is common, but brine springs less so, the evaporation of seawater has always been the major source of salt supply.
While in naturally warm climates such as the Mediterranean, it is economically feasible to use only solar evaporation of seawater to produce salt, in the colder climates such as the United Kingdom and Canada salt cannot be economically manufactured by solar evaporation. Instead, in the colder climates most salt before the late 1800s was made by evaporating seawater in large open pans with fires burning underneath (6). This was a somewhat inefficient process, and the key to producing salt economically by this method was to concentrate the salt solution in the seawater as much as possible by some other process before boiling the concentrated salt solution by a fire (10). Salt usually comprises about 3.5% of seawater (11). It follows that if one can find a natural efficient way to get rid of 50% of the water before boiling, then the cost of fuel for boiling drops by 50%, and if one can find a natural efficient way to get rid of 80% of the water then the cost of fuel for boiling drops by 80% and so on. The salt industry in the colder northern climates was therefore based around concentrating the salt solution as much as possible before boiling to save costs and therefore to produce salt as cheaply as possible.
An old historic method of making salt from seawater is described by Professor Le Conte as “lixiviating saline sand and then boiling the brine” (10). He records that salt is made by this method on a small scale in Normandy (he published his work in 1862). The tide is allowed to cover beach sand, which dries after the tide recedes, leaving a mixture of salt and sand. The sand is then removed to sheds, then is transferred to pits where seawater is added. The seawater dissolves the salt in the sand, thus increasing the concentration of salt in the water. The concentrated salt solution is then boiled to extract the salt.
A very similar method has been used for hundreds of years in Japan (11A). In the Japanese variant of this technology known as the Channelled Salt Terrace Method (Irihamashiki-Enden), the salt works is laid out on the shore below the level of high tide, and the tide is kept off the salt works by a dyke. The salt works comprise a flat area known as a salt terrace, with a layer of sand over the terrace and with channels running through the terrace area. Seawater is allowed to periodically flow through the dyke and down the channels, where the seawater permeates through the sand by capillary action. The sun and wind then dries out the sand leaving a mixture of sand and salt. The process is repeated multiple times, with the amount of salt in the sand steadily increasing each time. Finally the mixture of sand and concentrated salt is scooped up and put into tanks where a final inundation by seawater from the dyke occurs, which dissolves the salt in the sand to form a very concentrated solution of salt, which can then be boiled relatively cheaply to extract the salt.
A similar methodology was also used to manufacture salt in medieval Holland (12). Eel grass (zostera marina) was harvested from shallow saltwater areas, dried, and burnt. The resulting ashes had, as one would expect, a high salt content. Seawater was then added to the ashes, dissolving the salt and so increasing the concentration of salt in the water. The concentrated salt solution could then be economically boiled to extract the salt.
How the Finger Drains Could Have Been Used to Manufacture Salt on Oak Island
It appears there was a natural saltwater spring on the beach at Smiths Cove, Oak Island, because near contemporary accounts record it (13). It seems that Daniel Blankenship rediscovered the saltwater spring in 1970 (14). I therefore hypothesise a salt works at Smiths Cove was planned, constructed, and operated in this manner:
(i) An early fishing enterprise (perhaps Gifford & Smith in the 1750s?) was based on Oak Island, to catch fish from the then rich fisheries of the Atlantic coast of Canada. The enterprise required salt to preserve its catches of fish. If salt could be clandestinely manufactured on Oak Island, where it would escape the then punitively high salt taxes, then so much the better.
(ii) Because of the relatively cold climate of maritime Canada, producing the salt by solar evaporation was not feasible. The only way to manufacture salt economically on Oak Island was to concentrate seawater by one of the known processes used before the 1800s, and then boil the concentrated salt solution.
(iii) The fishing enterprise could have created a salt works in this manner:
· Build a cofferdam (or “dyke”) on the beach at Smiths Cove, shielding the finger drains area from the sea.
· Excavate the area inside the cofferdam, lay the five finger dams from the cofferdam converging to a common point at around the high water mark, cover the drains with a layer of beach rocks, spread a layer of eel grass and then a layer of coconut husk over the rocks, and finally spread a two foot (60 centimetre) layer of sand over the coconut husk.
· A well would be constructed at or near the point of convergence of the five finger drains (and in fact such a well was excavated by Dunfield in the mid 1960s (3) and he found it to be about 25 feet [8 metres] deep – he found it was a dead end and did not lead to any kind of flood tunnel (15)(16)).
(iv) The natural saltwater spring, and/or controlled amounts of seawater through channels in the dyke, would be allowed to permeate the sand on the artificial beach by capillary action. Wind and sun would dry the sand leaving a mixture of salt and sand. The process would be repeated at regular intervals until there was a considerable quantity of salt in the sand. In the meantime the tides would be kept off the beach by the dyke. Once sufficient salt had accumulated in the sand on the artificial beach, a larger than usual but still controlled inundation of seawater at high tide would be allowed through the dyke, covering the beach and dissolving the salt in the sand as the water dripped through the coconut husk and eel grass layers down through the rocks and through the finger drains to the well. The purpose of the coconut husk and eel grass layers was to sieve out any sand and silt from the concentrated salt solution before it reached the well.
(v) The seawater collecting in the well would have a high salt concentration as it would have not only the natural salt concentration of ordinary seawater but also the accumulated salt from the artificial beach sand. This concentrated salt solution could then be boiled to extract its salt.
(vi) Where would the concentrated salt solution be boiled? It would seem the concentrated salt solution from the well was boiled at an unusual structure discovered by Dan Blankenship about 150 feet [50 metres] south of the centre of Smiths Cove Beach in 1969, at a depth of about 2 feet [60 centimetres] (17). It was a concrete U-shaped foundation buried in the soil. In Dan’s own words:
“This foundation was quite massive. It was roughly 12 feet [4 metres] wide and 25 feet [8 metres] long with the end towards the shore open. The width of the footing varied from 20 inches [50 centimetres] to 30 inches [75 centimetres] and averaged 3 feet [1 metre] deep. All the stones were cemented together in a mass.”
Why do I think this structure was where the concentrated salt solution was boiled? Dan states that the earth inside the foundation “showed evidence of extensive heat and was burnt deep red ..... pieces of charcoal and coal were found in this area”. Now, the historic sites where saltwater was boiled in East Anglia, England, to extract salt are to this day identified by the soil being burnt a deep red colour (18). I would hypothesise the horseshoe shaped foundation was a fire pit over which large metal pans of concentrated salt solution were boiled, the pans being supported by the structure.
I will now endeavour to answer some queries in relation to the hypothesis that the finger drains are an abandoned salt works, probably from the 1700s.
Why is it plausible the finger drains are the remains of an old salt works? The finger drains and artificial beach above them echo known technology from the 1800s and beforehand used in Normandy and Japan for salt extraction from sand beds on or adjacent to sea beaches. Such technology could be easily adapted to the finger drains complex for salt production as hypothesised above. In fact, in many ways, the Oak Island finger drains are arguably a more efficient means of producing concentrated salt solutions than the methods used in Normandy and Japan, because the Normandy and Japanese methods were quite labour intensive, using manual labour to shift the sand/salt mixture to pits or vats where it was treated with fresh seawater to produce a concentrated salt solution, in contra distinction to the hypothesised Oak Islands salt works where I believe the salt-sand mixture was not moved at all but instead left in situ with the concentrated salt solution being produced by allowing fresh seawater to drain through the salt-sand mixture (dissolving the salt therein on the way) and then through the finger drains to accumulate as a concentrated salt solution in the well.
Why are there no written records of an Oak Island salt works? It seems plausible the Oak Island salt works was kept secret to avoid paying the punitively high taxes levied on salt at the likely time of history.
While salt is accumulating in the sand, how would they stop water percolating through to the well? Our readers will have already noticed that if too much saltwater is allowed to percolate into the sand, either from a saltwater spring or from controlled inundations allowed through the dyke, some of the saltwater might pass right through the sand and then through the finger drains to the well where the saltwater would not be concentrated on this scenario. It seems likely that in fact the amount of saltwater percolating into the sand was carefully controlled by:
(A) If there was indeed a saltwater spring at Smiths Cove, then the area and depth of the artificial beach was deliberately chosen to be large enough to ensure saltwater from the spring would spread via capillary action over a sufficiently large volume of sand that natural evaporation of the saltwater would be complete before the water got through the layers of coconut husk and eel grass so no water would in fact get through to the well from this source.
(B) Whether or not there was a saltwater spring at Smiths Cove, then the inundations of seawater through the dyke would be sufficiently controlled to ensure that the seawater permeating the sand on the artificial beach via capillary action would be completely evaporated by the time it reached the layer of coconut husk and eel grass so again no water in fact would get through to the well from this source.
However, what about rainfall falling on the beach? The depth of the sand (about two feet or 60 centimetres) seems sufficient to ensure that the water from a light to medium shower would evaporate before reaching the coconut and eel grass layers, so no problems. But a heavy downpour would admittedly result in the rainwater seeping right through the artificial beach and into the finger drains and so into the well. I suggest there would be two ways of handling this problem:
(a) The first solution would be to simply accept that it would happen from time to time, with the result that the salt accumulated in the beach on these occasions would be lost, and the water accumulated in the well would have to be ladled out and discarded. In other words, the harvest of concentrated salt solution from the salt works would simply be lost on those occasions where there was a heavy rainfall.
(b) Alternatively, during heavy rain, tarpaulins could be spread out to shelter the beach. I wonder if the famous U-shaped wooden structure in the Smiths Cove just seaward of the finger drains is the remains of a wood scaffolding designed to support tarpaulins spread over the artificial beach for this purpose? Photographs of such U-shaped wooden structure are available online (19). Certainly old salt works from the 1800s and earlier were often covered by portable roofs which would be removed to allow solar evaporation when the sun was shining and replaced when it was raining.."
Und jetzt kommen wir wieder zur Serie und warum man sie sich ansehen sollte wenn man über diese Dinge hier diskutiert: Genau diesen Bereich haben sie in der aktuellen Staffel trocken gelegt und ausgehoben. (war glaube ich noch nicht im Deutschen TV zusehen. Müsste in den nächsten 14 Tagen gesendet werden)
s..zwerg05 schrieb:Vielleicht solltest Du Dir die letzte Staffel erstmal ansehen und dann diskutieren. Läuft ja derzeit im deutschen TV....
