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planning test and major cxcavations. IHowcvcr, the initial rccording of t٢averscs
covering a large area is hclpful in locating areas where grids should be mcasurcd,
since the recording of conductivity of a grid is time-consuming. Thcrcfore, thc fial
dccision on where to carry out excavations is primarily bnsed on the rccording of ٠
grids, The interaction bctween the two nodes is vcry productive when applied to an
archaeological rcsearch plan.

Data Recording and Analysis

Conductivity data from cither a traverse or a grid was initially recorded on paper.
Line graphs and 2-dimensional contour plots were produced by recording the data
on grapl paper and manually drawing the contours between identical contour
values by interpolation. These initial plots proved to be beneficial in planning for
subsequent prospecting.

A more detailed and careful analysis of field data was accomplished using both
microcomputing and main frame computer facilities in the United States. A
LSI-11-based microcomputer at the Smithsonian Institution was used as an initial
data entry point for subsequent transfer via telephone lines to other mainframe
computers. Programs were written to allow interactive communication at maximum
efficiency and minimum cost between the L‫ﺶ‬I-11,a HoneywellvGCOS (located at
the Smithsonian lnstitution), and a HoneywellMultics (located at the U.S.
Geological Survey). Graphic projections were computed using a Radian Corpora­
tion CPS-1 contour plotting system on the HoneywelfMultics computer. The
CPS-1 program will use data derived from a regularly or irregularly spaced sample
of a smooth, continuous or faulted (discontinuous) surface., The program will
produce a variety of graphics, including contour plots,, various isometric projec­
tions, cross-sections, and profiles. Additionally, the program provides the user with
a variety of computations including determinations of volumes and areas (Radian
Coproration, 1979; Caruso and Pascal, 1980).

Measuremenst
For maximum accuracy, several fied test areas were created in which the

measured conductivity in mSlm and instrument calibration could be controlled
before, during, and after each survey session. Also, the weather conditions were
recorded before and during the suvreys. Although no rain was experienced during
the actual surveys, the few occurirng rainfalls were recorded so that all of the
suvreys could be carried out under the most similar climatic conditions. Also, the
instruments's response to different climatic exposures was tested. This was a
continuation of the studies carried out at the Bab edh-Dhra cemetery near the
Dead Sea in 1981. So far we did not ifnd any changes in the readings when the
EM-31 was exposed to either severe climatic conditions andlor changes in the
cliiatic conditions (Frohilch and Ortner, 1982). The question about repeatability

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