“Until recently geophysicists researching the earth’s magnetic field sent out survey parties with a magnetometer. Frequently the party had to hack its way through the bush to collect data. It was slow, expensive work. Today geophysicists can use a dramatic refinement of this old method—the airborne magnetometer. Carried by an airplane traveling at 125 miles per hour at an altitude of up to 1,500 feet, the airborne magnetometer can deliver accurate data on new oil and mineral resources at a rate of up to 10,000 square miles per month.”

Scientific American, January 1948

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