Two types of vacuum-tight joint have been developed for articulation of the connecting lines of a mercury manometer. The design and construction of each joint are described. The cylinder type has a seal around the circumference of a tube. The exit tube of the cylinder joint can be moved in a plane normal to the joint axis. The ball-and-socket type has a seal around the equator of the ball. The exit tube of the ball-and-socket joint can be deflected 15°. The joints are packed with Teflon and they remain vacuum tight without causing excessive resistance to movement.