Abstract: A control device in an anesthetic administering system which senses the dangerous condition of nitrous oxide flowing to the patient's breathing mask in the absence of oxygen flow to the mask and provides a warning signal so the condition is known and, thus, is correctable.

Abstract: In an electrical control panel, one relay can be stacked on the other as follows: Without removing an installed relay, the screws holding the octal base of the relay are replaced by adaptors which extend up from the base beyond the relay housing. Another octal base is mounted on the ends of the adaptors by screws threaded into the same from the second base. Another relay is then plugged into the second base. The two relays now are in stacked position. The adaptors have a yielding connection which allows the new relay and base to be moved to provide a clearance space for access to the first relay and then returned.