p. 375 | Cyclone and Tornado

Seventh-day Adventist Missionary Society · Oakland, California · Aug 24, 1882

Cyclone and Tornado.

The difference between a cyclone and a tornado is defined by Wm. Ferris, of the United States coast survey, in the Journal of Telegraphy, as follows: A cyclone is usually a broad, flat, gyrating disk of atmosphere, very much greater in width than altitude; a tornado is a column of gyrating air, the altitude of which is several times greater than its diameter. Cyclones are born of conditions extending over large areas; tornadoes depend rather upon the vertical relations of the atmosphere, and occur when, owing to the local changes of temperature, the under strata of air bursts up through the overlaying strata. The enormous velocities of the ascending currents of tornadoes are supposed to be caused by the difference between the gyrating velocities above and those on the surface. It is these ascending currents which carry up the vast bodies of water afterward precipitated in the form of a deluge of rain. The water is sometimes kept from falling by the ascending currents, and is often projecting outside the area of the tornado, when it falls in a gentle shower over a large area. When the weight of the water overbears the force of the ascending currents, there occurs the tremendous fall of rain known as a cloud-burst. When the area of the tornado is very small, a land-spout or water-spout may be formed, according as it is over land and water. The width of these spouts range between two feet and 200, and their height from 30 to 1,500 feet. A white squall is an invisible spout formed when the dew point is low. The accompanying cloud is invisible because of its height, but below there is a raging and boiling sea, with a gyrating current of air above it. Land-spouts and water-spouts are hollow. —Elmira Advertiser.