Science and research. Mineral prospecting. Chemical prospecting for oil becomes more and more important as the war goes on the demand for oil increases. Petroleum engineers call chemical prospecting the first scientific approach to the detection of oil in the earth. The big glass condensers, with which these engineering students are working with a professor of geophysics are used in a soil analysis test. The percentage of wax left as residue at the end of the experiment indicates the nearness of petroleum to the site from which the soil sample was taken. Colorado School of Mines, Golden, Colorado. Sourced from the Library of Congress.