NATATURE of a Tornado.—The relation of a tornado to human life and property depends upon its nature. What it does is determined by what it is. Briefly stated, a tornado is a very intense, progressive whirl, of small diameter, with inflowing winds which increase tremendously in velocity as they near the centre, developing there a counter-clockwise, vorticular, ascensional movement the violence of which exceeds that of any other known storm. From the violently agitated main-cloud mass above there usually hangs a writhing, funnel-shaped cloud, swinging to and fro, rising and descending. With a frightful roar comes the whirl, advancing almost always towards the north-east with the speed of a fast train (twenty to forty miles an hour or more), its wind velocities exceeding 100, 200 and probably sometimes 300 or more miles an hour; its path of destruction usually less than a quarter of a mile wide; its total life a matter of perhaps an hour or so. It is as ephemeral as It is intense.