Abstract: An improved means for magnetically operating push buttons and other controls on cameras in underwater housings is disclosed. The magnetic force of repulsion is employed to transmit motion through the case wall without electrical connection to the camera or sliding or twisting or flexible seals.

Abstract: An improved means for magnetically operating push buttons and other controls on cameras in underwater housings is disclosed. The magnetic force of repulsion is employed to transmit motion through the case wall without electrical connection to the camera or sliding or twisting or flexible seals.

Abstract: An apparatus and process for measuring bulk material flowing in a pipe by light reflection, the pipe having at least one window (24a,24b,24c) consisting of a light-transmissible material, an analyser (19) being arranged outside the at least one window for emitting light and measuring the light reflected by the bulk material in the pipe, characterised in that the pipe has an elbow having a first pipe section (14) at its entrance side and a second pipe section at its exit side, at least one window being provided in a plate (9) at the outside of the elbow, which plate is arranged at an angle to the axis of the first pipe section.