“You are seeing the parts of the ship and its mechanism which your mind is capable of grasping. The large drum like structure just above the central bulkhead is the differential accumulator. It is essentially a storage battery which is capable of being charged from any of a number of natural energy differentials which may be available. By the word `charged,’ I merely mean that a potential difference is created between two poles of the accumulator. The material of the poles has available free electrons in quantities beyond anything of which you could conceive. The control mechanism allows these electrons to flow through the two force rings which you see at the top and bottom of the craft. You are familiar enough with electrodynamics to know that a moving electron creates a magnetic field. The tremendous surge of electrons through the force rings produces a very strong magnetic field.