science as yet has not been able to grasp the laws that govern cyclones. they seem to be the result of some intensely electric condition of the elements, which finds an expression in that form. cyclones, until within a few years, meant those circular tempests encountered in the pacific and indian oceans. they are the most destructive of all storms, being far more deadly than monsoons and tornadoes.
all navigators, when caught in a cyclone know how to get out of it. they have only to sail at right angles to the wind, when they will either pass beyond the outer rim of the circular sweep, or reach the center, where the ocean is calm.
the diameters of the ocean cyclones range from fifty to five hundred or a thousand miles. professor douglas, of ann arbor university, entertains his friends now and then by manufacturing miniature cyclones. he first suspends a large copper plate by silken cords. the plate is heavily charged with electricity, which hangs below in a bag-like mass. he uses arsenious acid gas, which gives the electricity a greenish tint. that mass of electricity becomes a perfect little cyclone. it is funnel-shaped and spins around like a top. when he moves the plate over a table, his cyclone catches up pennies, pens, pith balls and other small articles, and scatters them in every direction.
cyclones never touch the equator, though the ocean ones are rare outside the torrid one. they are caused by the meeting of contrary currents of winds, and are known under the names of hurricanes, typhoons, whirlwinds or tornadoes. those terrifying outbursts which now and then cause so much destruction in our own country seem to be the concentration of the prodigious force of an immense ocean cyclone within a small space, which renders them resistless.
a writer in the n. y. herald gives some interesting facts regarding these scourges of the air. while the cyclone, as we have shown, may have a diameter of hundreds of miles, the track of a tornado is often limited to a few hundred feet, and rarely has the width of half a mile.
the cyclone carries with it a velocity of as much as 100 to 140 miles an hour. it sends a certain amount of warning ahead of its track, and the acceleration of the wind's speed at any given point, is gradual.
the tornado falls almost without notice, or rather the indications are often so similar to those of an ordinary thunderstorm that only a skilled and careful observer can detect the difference.
the phenomena and effects of cyclones in the west indies have long been subjects of study and observation. as the center approaches a ship she is assaulted by wind of a terrible force and a sea that is almost indescribable. the water no longer runs in waves of regular onward motion, but leaps up in pyramids and peaks. the wind swirls and strikes until wherever there is a chance for vibration or flutter, even in tightly furled sails, the fabric soon gives way. i once saw a brig go drifting past us in a west indies cyclone with everything furled and closely lashed with sea gaskets. we were in company nearly at the height of the storm, when the center was only a few miles away. there was a spot in the bunt of the foretopsail where the sail was not tightly stowed, and for several hours it had doubtless been fluttering under tremendous pressure. as i watched her a little white puff went out of the bunt of the topsail, and then the destruction of the sail was rapid. long ribbons of canvas went slithering off as if a huge file had rasped the yard arm, and in a short time there was nothing left on the yard except the bolt ropes and the reef tackles. we could do nothing to help the crew, for it was doubtful whether we could keep off the reefs ourselves, and the brig passed out of sight to her certain doom.
the local tornado that so frequently plays havoc with property and life in the west is, like the cyclone, a revolving force, but it carries with it a variety of phenomena wholly distinct from those that accompany the larger storm. many of the effects of one tornado are wholly absent in others, and the indications that in one case have been followed by a terrible disaster are not infrequently found at other times to presage merely a heavy thunder shower.
the freaks of a tornado are wholly unaccountable. in some cases not an object in its track will fail to feel its power for long distances; in other instances it will seem to act like a cannon-ball that plows up the earth on striking, then rises and strikes again, leaving the space between untouched. sometimes it will go through a forest leveling the trees as though a gang of axemen had plied their tools on lines laid out by surveyors, nothing outside the track being touched; but again in similar windfalls there will be found occasional pockets scored in the forest growth jutting off the right line, like small lagoons opening into a flowing stream. these seem to have been caused by a sort of attendant whirlwind—a baby offspring from the main monster, which, having sprung away from the chief disturbance, scoops a hole in the woods and then expires or rejoins the original movement.
i have seen one of the most violent and, so to speak, compressed of these storms, cut a road through thick woods so that at a distance the edges stood out clear and sharp against the sky as would those of a railway cutting through earth. trees standing at the edge of the track had their branches clean swept one side while on the other there was no perceptible disturbance of the foliage.
sometimes the tornado acts like an enormous scoop, catching up every movable thing and sweeping it miles away: and again it becomes a depositor, as if, tired of carrying so much dead weight, it dumped it upon the earth preparatory to grabbing up a new cargo. these effects are particularly noticeable in the tornado that goes by jumps. when it strikes and absorbs a mass of debris it seems to spring up again like a projectile that grazes the surface. for a space there will be a very high wind and some damage, but no such disaster as the tornado has previously wrought. out of the clouds will come occasional heavy missiles and deluges of water. then down goes the tornado again crashing and scattering by its own force and adding to its destructive power by a battery of timbers and other objects brought along from the previous impact. relieved of these masses, it again gathers up miscellaneous movables and repeats its previous operation.
the force with which these objects strike is best seen when they fall outside of the tornado's path, since the work done by the missile is not then disturbed by the general destructive force of the storm. thus, near racine, wis., i have known an ordinary fence rail, slightly sharpened on one end, to be driven against a young tree like a spear and pierce it several feet. the velocity of the rail must have been something enormous, or otherwise the rail would have glanced from such a round and elastic object.
many of the settlers in the tornado districts of southern minnesota, iowa, kansas, and nebraska excavate a deep cellar beneath their houses and cover it with heavy timbers as a place of refuge for their families when a tornado threatens to strike them. while these dugouts are usually effective, they are not always so. there have been instances where families having only time to descend and not time enough to close the trap door have been exposed to the storm's full fury by the tornado getting into the opening and lifting off the whole roof after having first swept away the house above. another pathetic case resulted in the death of a whole family by an extraordinary freak of the tornado. the storm first struck a large pond and swept up all the water in it. its next plunge deposited this water on one of these dugouts, and the family were drowned like chipmunks in a hole.
some of the western tornadoes are accompanied by electrical manifestations to an extent that has originated a belief in electricity as their cause. these disturbances are very marked in some cases, while in others they have not been noticed. in one tornado in central illinois electricity played very peculiar antics not only in the tornado's track, but also at some distance from it. in the ruined houses all the iron work was found to have been strongly magnetized, so that pokers, flatirons and other metal objects were found adhering to each other. just off the tornado's track the same effects were noticed, and several persons experienced sharp electric shocks during the passage of the storm. afterward it was found that the magnetic influence was so strong that clocks and watches were stopped and rendered wholly useless.
the scooping action of the tornado sometimes makes considerable changes in the topography of the country, as when it gathers up the water of a large pond or water course and makes a new pond or opens a new channel. at wallingford the water in a pond of very large size was taken bodily from its bed, carried up a hill and dropped nearly in one mass, so that gullies and ravines were cut in every direction.
there is a divide in northeastern illinois between streams flowing into lake michigan and those running to the mississippi. so level is a portion of the land on the summit, and so slight the elevation above the lake, that in wet seasons the surface-water seems almost as willing to go one way as the other; and on one occasion the upper streams of the desplaines river were nearly permanently diverted toward the lake by a tornado that gathered up the water and scored the surface in its track toward the east.
many are the stories told of the way in which objects are carried away by the wind and left in strange places. in one illinois tornado two children and an infant were caught up. the dead bodies of the children were found only a few hundred feet distant, but the infant was picked up alive more than a mile away from the spot where the tornado swept the children up. an accordion that must have come a long distance—for it was never claimed—was found so entangled in the branches of a tree that it was alternately pulled apart and pressed together by the wind, thus creating such weird and uncanny music during a whole night that an already sufficiently scared settlement of negroes were kept in a state of frantic dismay until daylight revealed the cause.
in another case a farmer who followed the tornado's track in search of missing cattle was astonished to discover one of his cows lodged about twenty feet above the ground in the branches of a half-stripped maple.
"i allers knew that was an active heifer," he remarked, as he came in sight of her hanging over the slanting limb, "but i never allowed she could climb a tree."