Page 43 - J. C. Turner "History and Science of Knots"
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32                      History and Science of Knots

               1. A completely dry environment, accompanied by rapid desicca-
                  tion of the material itself;
               2. Permanent sub-zero temperatures;
               3. Permanent saturation of the material and its environment with
                  water, thus creating an oxygen-poor environment;
               4. Chemical reactions, resulting in alteration and preservation of
                  the material.
              Even under these extreme conditions disintegration is usually only slowed
          down, not stopped altogether. The further we go back in time, the smaller our
          chances are of finding intact the fragile materials used for knotting.
              Permanent conditions of extreme dryness or extreme cold are rarely found
          in the temperate zones of middle and northern Europe. These regions there-
          fore have not, and will never, produce the impressive amounts of textiles,
          basketry and ropework found in, e.g., Egypt and the American Southwest-
          with, however, one recent exception, which will be dealt with later.
              Waterlogged conditions, however, do occur quite frequently; and here our
          relatively cool climate is an advantage, for the lower the water temperature,
          the more the processes of disintegration will slow down.
              Chemical preservation is also found fairly often. Thus, quite a few textile
          fragments have been preserved because they were in close contact with copper
          or copper-containing objects, such as brooches and beltplates. A combination
          of chemical preservation and saturation with water has preserved many bog
          finds from all periods, but especially impressive is the large number of rope-
          and textile-fragments, complete clothes, and finally well-preserved human bod-
          ies from the Iron Age.*
              Our information about knotting in the European stone age comes almost
          exclusively from waterlogged sites, including bogs. Quite a few of these sites
          have been found, and more will be found and properly excavated, as the tech-
          niques and the knowledge necessary to excavate especially under-water sites
          are further developed. But at the same time, this introduces a bias in the
          sample of preserved knots. The vast majority of sites that were waterlogged
          when discovered were also originally located in or near water: bogs, the shores
          *Iron Age: in northern Europe, the start of the Iron Age is conventionally placed at around
          2600/2500 B.P. (B.P. = Before Present). All dates given in this article are calibrated ones:
          i.e. the dates obtained through C14 measurements have been corrected by allowing for
          fluctuations in C14 content in the atmosphere, as they are now known to have occurred
          (formerly the C14 content was assumed, wrongly, to have remained constant throughout
          the ages). The differences between calibrated and uncalibrated dates can vary from so small
          as to be negligible , to almost one thousand years. The latter is the case for a large part of
          the mesolithic and neolithic periods. Hence it is important to declare whether dates used
          are calibrated or uncalibrated ones.
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