Around 1985, Jones became interested in anomalous concentrations of helium-3 and Tritium found in gases escaping from volcanoes. He hypothesized that metals and high pressures in the Earth's interior might make fusion more likely, and began a series of experiments on what he referred to as geo-fusion, or "piezofusion," high-pressure fusion. To characterize the reactions, Jones designed and constructed a neutron counter that was capable of accurately measuring minuscule numbers of neutrons produced in his experiments. The counter indicated that a small amount of fusion was occurring. Jones claimed that the results indicate that fusion is at least possible, although the process was unlikely to be useful as an energy source.