Abstract: A method and device for testing the quality of a ground path, particularly although not exclusively for a telecommunications system. The device has terminals for connection to respective lines, such as tip and ring. A terminal is provided for connection to the local ground. Voltage-sensitive switches of increasing threshold voltage are alternatively connected between the local ground and each of the tip and ring lines via a rotary or other selector switch and the terminals. Current will flow if the local ground potential exceeds the threshold voltage of the voltage sensitive switches. A device responsive to mains frequency, e.g. a butt-in head set, provides an audible sound (mains hum) indicating the ground potential rise exceeds the threshold of the selected voltage-sensitive switch.

Abstract: An adjustable lamp is provided (FIG. 1) comprising a main arm 12 which is pivoted to a base at one end and carries the lamp housing at the other end. The angular position of the arm relative to the base is controlled by a link also pivoted to the base and to a sliding connection on the arm. There is adjustable frictional resistance to sliding, and additionally the link is spring urged to counterbalance the increasing turning moment as the arm moves towards the horizontal position.