The Economic Times

Built to hunt enemy submarines during World War II, this device later transformed our understanding of the seafloor

World War II fluxgate magnetometer: A World War II device found new scientific purpose after the war. Oceanographers refitted the fluxgate magnetometer for seafloor magnetic anomaly measurements. These measurements revealed symmetrical patterns on either side of mid-ocean ridges. The magic profile provided strong evidence for seafloor spreading and plate tectonics.