There exists a force in nature which is far more powerful than steam, by means of which a single man, who can master it, and knows how to direct it, might throw the world into confusion and transform its face. It is diffused throughout infinity; it is the substance of heaven and earth. When it produces radiance it is called light. It is substance and motion at one and the same time; it is a fluid and a perpetual vibration. In infinite space, it is ether, or etherized light; it becomes astral light in the stars which it magnetizes, while in organized beings it becomes magnetic light or fluid. The will of intelligent beings acts directly on this light, and by means thereof, upon all nature, which is made subject to the modifications of intelligence.