181. In the case of purely mechanical mediums, the movement of the hand is independent of the will; with the intuitive medium, that movement is voluntary. The semi-mechanical medium participates in the qualities of both the others; he feels an impulsion that is given to his hand, independently of his will, but, at the same time, he knows, as he goes on, what he is writing. With the mechanical medium, the thought follows the act of writing; with the intuitive medium, it precedes it; with the semi- mechanical medium, it accompanies it. These last named mediums are the most common of all.