the Walking across Live Coals; and the Climbing upon Sword-blades, all depend upon it for easy performance. That the average Japanese sole is equal to the feat without preliminary purification is evident from the success of my boy, who simply picked up his skirts and walked.
But a certain other physical fact enters this last miracle not commonly appreciated, to the innocent manipulation of which by the priests the miracle is due; to wit, the immense difference in cutting power between a stationary and a moving blade. Everybody is aware that there is a difference, but few people realize how very great it is. If you press your finger upon the sharp edge of your knife, you will be surprised to find what a pressure you can put upon it with impunity; but if, ever so gently, you draw the knife-blade across the skin, it instantly sinks in.
The principle involved is the principle of the wedge. By drawing the blade along in the direction of its edge at the same time that you press down, you thin its angle to any desired tenuity. You have but to graduate the horizontal motion to the vertical