Abstract: The invention is comprised of a heat exchanger around the exhaust stack of any combustible fuel-burning system and also around the outside of any fuel-burning device; each heat exchanger filled with a porous heat-conducting material so that fresh outside air pulled by motor-powered means into any building operates to replace the cold air therein with fresh warm air pre-heated from the combustion device and stack.

Abstract: The invention disclosed herein is comprised of an electric generator powered by an electric motor that is activated by any source of electricity so that the torque of the electric motor reacting against its stator assembly and the action of the stator of the generator resisting the magnetic force of its rotor both act to electrically indicate the differences in acceleration of gravity and other accelerations when electrically-measured by electric current-measuring means.

Abstract: The invention is comprised of an electric motor and generator whose moving parts are connected to each other by torque-transmitting means so that the torque of the electric motor and the resistance of the electric generator operates to lift either the electric motor or generator for a distance against the force of gravity. The distance is determined by a mercury-type electric switch and the differences in gravity at different places above the Earth are measured both by a motor ampmeter and a generator ampmeter to detect minerals and water beneath the surface of the Earth.