Dowsing Archaeological Features;
An empirical study at Cressing Temple, Witham, Essex.
Using dowsing techniques to locate archaeological features is not a new concept. Authors like J. Scott Eliot who in 1977 wrote a compilation of case studies in 'Dowsing; One man's way and the British Society of Dowsers who produced 'Dowsing and Archaeology' in 1980 testify to the commonality of reports for the last thirty years.
Unfortunately the unscientific way in which the reports are presented and the almost complete lack of comparative results has only served to fuel scepticism not only about the validity of the technique but also of the honesty of the practitioners themselves. It is often suggested in these texts that the dowser should 'have in mind what he seeks'. This of course implies that one already knows what is to be found or that one is inclined to invent something to fall in with the expectations of the project.
During the test day several participants asked what it was they were looking for and one in particular was adamant that he would find nothing if he did not have a goal. This proved to be false and the participants were asked to look for responses not itemised features. Wishful thinking certainly played a part in some peoples findings and others were influenced by the grid that was laid out for the survey. Misunderstanding of how and what to record also affected the results but only as a model for human behaviour.
Analysis of the plots made shows definite trends which can be specifically linked to known and supposed features. This basis can be refined later with electronic remote sensing or excavation and costs can be significantly reduced by concentrating on areas that give strong and repeated responses.
It is interesting to note that the remote sensing survey of the centre of the monument failed to locate all but the strongest reactions because of the heavy landscaping and surface levelling. Most notably the edge of the excavation BVAS IV which was backfilled only twenty years ago does not appear whereas the dowsing exercise clearly located the eastern edge as well as the later excavations CT29 T1/ T3.
Colin Peal's work while being more comprehensive and structured in appearance is subject to the same inconsistencies as the test day surveys. He is ready to admit that he had no real idea of what he was trying to achieve and that he had little dowsing experience at the time he began his work. The measurements he made are limited in their accuracy by how far the responses are from fixed points on the plans he was supplied with. He used tapes and triangulation, a technique whose accuracy drops off with distance.
This borne in mind, however, it cannot be denied that he has an impressive rate of coincidence with the physical features. He scores most strongly on brick structures and compressed footings such as the chapel, stone hall, cellars and drains. These readings are constant and subject in strength only with the variation in ground moisture. There is some seasonal drift in position due to the changing magnetic field of the earth but this is limited to a scale of metres at the most.
Where scepticism must be addressed is where responses that are clear and recorded lead to no discovery. There can be a number of reasons for this such as underlying geology, deeply buried features (perhaps below the glaciation) and misleading responses created by modern materials. An example of this might be a concrete floor, mole or tube field drains, or as in the case of the pigyards at Cressing Temple a thick layer of gasworks brieze brought in as hardcore which completely masked the underlying features. The concept of remanence also falls into this category and may be particularly applicable to timberframed and other ground-fast buildings.
A further reason for the failure to discover major features is that of preconception. The idea that we already know what is to be found and so there is no impetus to look further in a particular area was demonstrated on the south-west corner of the 'Greate House'. Here Colin was told his findings represented buried cattle grids so he did not record them. A lesson for the future.
Barry Hillman-Crouch. MSt PA, Dip FA, BSc, HND. Written 1999 Published on the web June 2005.