Abstract: A mounting bracket including a base which accommodates more than one fastener. A latch mounted on the base that discourages removal of the fasteners from the base. The latch cooperates with the base to define a capture zone that selectable secures the wire of a picture or like article. The base also includes a catch which may retain the latch from cooperating with the base to capture a wire. The base further includes a marking element which may be used to mark a position on a wall. Methods of mounting and hanging articles also are disclosed.

Abstract: An ion mobility detector comprising a one piece dielectric tube with conductive bands as field elements for accelerating ions formed in a reactor region of the tube and passed to a drift region of the tube under control of a gate separating the reactor region from the drift region and thence to an electrometer plate. A first d.c. voltage source provides operating voltages to the conductive bands while a separate d.c. voltage source provides operating voltages to the gate. The detector includes circuitry for varying the potential of the gate to ensure correct focusing of ions within the cell. The circuitry includes an arrangement for altering the potential of the gate. The arrangement can be automatically controlled as a function of the output of an amplifier connected to the electrometer plate.