PROCEDURE:

The Koolau rock, heavily coated with polyurethane, was placed in the oven along with a thermometer and a temperature probe (Sentel Assoc.). The walls of the oven are approx. 3" thick (thermally insulated). The two (inner and outer) metal surfaces are grounded so that the rock is electrostatically shielded. Heating elements and thermostat are located within the side walls.

Self-potential output is conducted directly to Austin stripchart recorder No. 1. Readings are in millivolts. See attached chart.

RESULTS:

Strong diurnal variations are observed, also a secular drift, which do not correlate with any temperature fluctuations within the oven. The phase relationship appears similar to that of Catalina granite in Test No. 105.