This may be done by hand or with a mechanical device. There were no air tanks and any other sort of mechanical device was forbidden. Instead of a mechanical device, Feldman imagined wetware. An operating temperature is the temperature at which an electrical or mechanical device operates. Talks through a mechanical device attached to his neck. Auditing was composed of conversation and not led by a mechanical device. Initially, the axle was lifted by a mechanical device. An example of a mechanical device which is bistable is a light switch. He was also the first to experiment with a wind-powered mechanical device, a windwheel. A propulsor is a mechanical device that gives propulsion. Thus counting revolutions with a mechanical device attached to the wheel measures the distance directly. Homogenization is achieved by a mechanical device called a "homogenizer". Predating digital computing, the Sensorama was a mechanical device. The Van de Graaff generator is a simple mechanical device. This idea spawned a whole new type of mechanical device known as the "trade stimulators".