Does any one knows something about the "Willis Generator?"?

A few months ago one of our reps told me about a strange device that generates power using the earth’s magnetism, I can’t recall what it was called but I can recall he told me it’s was called the “Willis generator”. I tried to find information on this device but did not find much info on this thing. He told me it was a secret device used in world war two submarines. It sounds too good to be true.