It is provide a method for determining at least one of physical, chemical and biological properties of a medium with the aid of at least two transmitter-receiver pairs and on the basis of at least one first and one second acoustic wave. The first acoustic wave has propagated at least in part between a first transmitter-receiver pair through the medium and the second acoustic wave has propagated at least in part between a second transmitter-receiver pair through the medium, wherein the medium adjoins an inner lateral surface of an elongate conduction element that is arched transversely to its direction of longitudinal extent.