Abstract: The apparatus and method of the present invention facilitate surveys of buried structures, such as pipelines or the like, in particular by substantially automatically measuring and indicating distance information. Preferably that information is obtained by a transducer that produces serial data representing the length of wire bailed out from a portable reel and a cyclical counter responsive to such data for counting the serial data. A signalling device, such as a horn, strobe light, etc., is activated each time the counter completes a cycle as an indication that a predetermined distance has been covered since the last measurement was made and that the next potential measurement should be made. The number of pulses of such serial data counted in each cycle of the counter can be manually adjusted to obtain small or large distance intervals between test locations at which potential or other measurements are to be made to obtain a substantially continuous survey of the pipeline.

Abstract: A reference cell for conducting closely spaced buried structure-to-soil electrical surveys uses a soil contact cell adapted to be mounted on the lower end of a pole or cane to be held by the surveyor walking over the right-of-way of the buried structure such as an underground pipeline. The cell includes a fluid chamber on the lower end of the pole or cane and includes on the lower end of the chamber a ground contact pad. A spring loaded bottom wall or boot closes the chamber and is operative to reduce the volume of the chamber when the lower end of the chamber is forced by the pole into contact with the ground above the buried structure. The reduction in volume of the chamber forces fluid through the contact pad to the ground to insure good electrical contact. Fluid in the chamber may be continuously replenished by a make-up supply carried by the surveyor which is drawn from the supply by return of the boot to its unstressed state.

Abstract: An apparatus for making electrical surveys of structures contained in an electrolyte by measuring potential difference therebetween includes an electrode to contact the electrolyte proximate the structure, a wire electrically and mechanically connecting the apparatus with the structure, and an electronic system for automatically electrically sensing and storing the potential difference values taken at a plurality of locations along such structure. In the method for making structure-to-electrolyte potential difference surveys a supply of elongate electrical conductor is electrically and mechanically connected to the structure; the conductor is played out along the structure, and the electrolyte is contacted at plural test locations proximate the structure; and the potential difference at such test location is automatically sensed and stored.