By his repetition of thought in connection with his problem, carried on over a long period of time, through thousands of experiments, Mr. Edison either consciously or unconsciously charged his subconscious mind with a clear picture of his problem, and, by some queer power which no one understands, his subconscious mind handed over to him the solution to his problem, in the form of a ‘hunch’ that caused him to think of the charcoal principle.
