A machine, such as a seed drill, has a conveying member for seeds or the like defining a path along which seed or other material is conveyed in discrete units during normal operations. The machine has an indication arrangement including a distance measuring instrument comprising a proximity sensor adjacent the conveying member for monitoring the pressure of material as it is moved along the path defined by the conveying member. A display panel connected to the distance measuring instrument renders occurrences comprising the movement or lack of movement of the material as sensed by the distance measuring instrument sensorially perceptible.