Abstract: An oil spill sensing/communicating apparatus which is buoyantly situated, anchored or adrift, in a salt or fresh body of water, featuring a configuration which permits fluid passage therethrough of surface water/oil and sensing of hydrocarbonous gas which is emitted/exhaled from the oil. The apparatus thus functions effectively regardless of visual conditions because it "smells" rather than "sees" the oil which is present. Oil detection is signaled by the apparatus via light transmission and/or via radio transmission of location coordinates; some adrift embodiments use the Global Positioning System of satellite communication for continually updating the radio-transmitted location coordinates.

Abstract: A technique and sensor is provided for directly measuring the thickness of ayers of immiscible liquids of differing densities and other materials contained in a tank or other container, preferably by reflection of ultrasonic energy. A preferred form of float comprises a container filled with material sampled from the tank and includes a reflector of ultrasonic energy of greater density, whereby the reflector is accurately positioned at an interface between two immiscible liquids of differing densities. The float is restrained close to the axis of energy radiation of the ultrasonic transducer by either a tube, forming a housing or a flexible cord. If a tube is employed, a slit in a lateral side thereof allows the tube to act as a baffle and reduce the effects of fluid motion within the tank on the measurement being made.