A Field at Ninefold
A rectangle of elevated dispersion in an open field, with edges sharp to thirty centimetres. Twenty-three years later it was the same size, and 1.9 metres further north.
The Survey's open-ground work is mostly done to get numbers for the register. A field with nothing in it is a useful thing to have measured: it gives you a floor that no building can give you, and every few years somebody uses it to check that an instrument has not drifted.
Ninefold was chosen in 1981 because it was flat, large, empty, and eight minutes from the operator's mother's house. It has been on the register ever since for entirely different reasons.
The 1981 survey
Instrument 01 was walked on a 5 m grid across roughly four hectares. The floor came out at 0.9°, which is about as low as ground gets. In the north-east quarter, one grid station read 4.6°.
Standard practice at that point is to abandon the grid and close in on the anomaly by halving, which the operator did, and which took the rest of the day because the thing did not behave like an anomaly. An anomaly from buried ferrous material has a soft edge: it climbs over a metre or two, peaks, and falls away. This had a step.
| Time | Instrument | Reading | Entry |
|---|---|---|---|
| 9 Aug 11:20 | 01 | 0.9° | Field floor, established over 61 grid stations. |
| 9 Aug 13:05 | 01 | 4.6° | Grid station NE-14. Anomaly located. |
| 9 Aug 14:40 | 01 | 4.1–5.2° | Interior of the region. Elevated throughout, no internal structure, no peak. |
| 9 Aug 15:10 | 01 | 1.0° | One pace outside the western edge. |
| 9 Aug 15:12 | 01 | 4.4° | One pace inside the western edge. Transition measured at 0.25 m. |
| 9 Aug 16:30 | 01 | — | Region measured and pegged. 11.4 m × 4.2 m, long axis on 108°. Corners square to within 2°. |
Edge positions are the midpoint between the last station reading under 1.5° and the first reading over 3.5°, walked in from four directions. The transition width is under 0.3 m on all four edges.
It is a rectangle. It is a rectangle with square corners and sharp sides in the middle of a field, and it is 11.4 m by 4.2 m, which is the footprint of a modest building.
What it is not
There has been no structure on that ground within the documentary record. The Survey checked the tithe map, the enclosure award, the county series Ordnance Survey from 1886 onward, and the 1946 RAF vertical photography. The field is a field in all of them.
In 1982 the landowner permitted a resistivity survey by a county archaeological unit, at the Survey's expense. It found no wall footings, no ditch, no robber trench, and no significant variation of any kind within the rectangle or around it. The unit's report is in the file and its covering letter is politely puzzled.
We also did the obvious things. We checked for a buried service and found none on any statutory plan. We dug two 0.5 m test pits inside the region with permission and found plough soil and then clay. We took the meter through it at 300 mm and at 1.5 m above the ground and got the same figures at both heights, which is not what a buried source does.
The re-survey
In 1982 the region was measured again from three fixed points on the field boundary and found unmoved to within the tolerance of the tape.
In 2004 it was measured from the same three fixed points. It is 11.4 m by 4.2 m, long axis on 108°, corners square. The floor inside it is 4.3°. The field floor is 0.9°.
Its centre is 1.9 m from where it was, on a bearing of 022°.
What we can say
The region is real, in the sense that four operators across twenty-three years and four generations of instrument have walked into it and out of it and got the same step. It is not an instrument fault; the 1981 and 2004 surveys share no hardware.
Ground moves. Ploughing moves the top 250 mm of it every year and has done throughout. Nothing in the subsoil moves 1.9 m in twenty-three years, and nothing that has moved 1.9 m in twenty-three years keeps its corners square to two degrees while doing it.
The Survey has no mechanism to offer and is not going to invent one. What it has is three sets of figures, a set of pegs, a resistivity report, and a rectangle in a field that is not where it was.
Cause not established.
A rectangular region of elevated dispersion with edges sharp to within 0.3 m, reproduced across three surveys and two instrument generations. Its position in 2004 differs from its position in 1981 and 1982 by 1.9 m on a bearing of 022°. No mechanism is offered.
The Thinplace Survey is invented and so is this file. The case files are horror fiction written in the format of a field report. The instruments they describe are real and are explained in full; the incidents are not.
Fiction