Abstract: A plurality of arcuately spaced transceivers for emitting and receiving radiation waves are positioned in a plane transverse to a molten metal stream. Each transceiver emits a radiation wave which is directed toward and reflected from the stream and the reflections are received by the transceivers. The time elapsed between the emitting and receiving of the radiated waves is measured for each transceiver. The time elapsed information is fed to a binary counter for each transceiver and the binary counts are averaged and processed in a computer to calculate the stream area. The rate of change in area of the stream in the transverse plane is determined, or alternatively the velocity is determined by measuring the time elapsed for a particular stream area to traverse a predetermined distance and fed to a computer which computes stream velocity. The velocity and area measurements of the stream are used to determine the stream volume. A programmed pour rate is then compared with the stream volume.