Morning journal and courier., 1882-08-18
Friday Morning, August IS, 1882.
TORNADOES. .


 study of the nature and causes of tornadoes to the September number of the North -1naeT1c0n ReUietD tornado, says MT. Maury, 'consists of mass of air in violent gyration, within which there is a center of rarefed air rising upward and flowing out above, the velocity of the surrounding at- mosphere, drawn into the vortex below, in- creasing immensely as it hears the vacuum. i" Though ln one sense small cyclone tie tor nado has peculiar center, not disk-shaped as that of the regular cyclone. ''The torna- do center may be conceived of as rapidly rotating, tall and somewhat cylindrical body, moving erect or slightly inclined over the earth, and powerfully drawing up into it's vortex all movable matter on the surface The funnel shaped cloud is formed around the upper part of the central whirl by the condensation of vapor carried up to colder regions, and also, probably, by the cold northeastern wind, which rushes into the rear of the storm" If the tornado center is what 1t Is supposed to be it can, MT. Maury points out, hardly be conceived of as working it's own way, with the tremendous velocity at- tributed to it, by the process of continual re-
 
 due to the impulses it receives from the great atmospheric current in which it forms, and it's velocity must be substantially that of any body borne along mechanically Gas an eddy in rushing stream of water) by the aerial currens in which it is suspended
 The true tornado is most frequently de. veloped in or near the extra tropical regions where the great anti trade currents encounter the polar winds: The existence of an atmos. pheric current flowing from the tropics in & northeasterly direction over the Mississippi valley during the summer months has been demonstrated. At the same time current of cold air is moving toward the equator. Any chance stoppage of one of these cur rents, says MT. Colding of Copenhagen, s'wiii cause it to inpinge against the other, either from the northwest or southeast, thus pro- duoing an eddy that moves against tho sum- The eddying winds thus formed under ex- traordinary circumstances may increase to tornadoes or hurricanes A striking confir- nation of this conclusion is presented by the general direction of tornadoes, which is identical with that of the upper trade wind and the anti trades. The time of greatest danger in tho Gulf States is the early spring !; in the upper Mississippi and Ohio valleys the early summer. In the later summer they sometimes, though rarely, visit the Atlantic States lying north of Maryland; the south ern and higher Alleghanies seem to be an effectual barrier against them. Whom autumn sets in the danger is practically over.
 In discussing tho question Can tornadoss be foreseen and predicted? Mir. Maury points out that the barometer does not neces- sariiy fall with the approach of the most fatal tornado, and the mercury may even rise in the instrument short time before the we'll marked signs of the storm appear. But when an area of low pressure is passing near and north of place, with an area of oompara- lively high pressure struggling to get into it's rear, the conditions are present for the for nation, or, more correctly speaking, for the descent of an already formed tornado. AS the critical hour of it's appalling approach draws near, the painfully still and sultry air, tho strange commotion in the upper atmos- phere, violent whirling of the clouds, " 'sscud clouds moving in different directions, " the upper clouds moving briskly north ward, indicating the existence of southerly upper current" vast volume of s"inky black and low moving clouds, ''sometimes of 'dun J ''dark blue," or ''coal smoke'' color illumin- ated by electric discharges, occasionally in the shape of 8 funnel, or inverted cone, or an hour glass, are among the surest and most carefully observed premonitory signs of the tornado's deafening roar although it's omi nous noise is sometimes audible half an hour before it's arrival. With such sky portents says Mir. Maury, it is obvious that loca weather watcher, arprised by timely weather bulletins of the existence of conditions favor l ing the generation of tornadoes, would be in position to forewarn western village o, ! town of impending danger. But it is proba ble that for local warnings of this kind each 1 community will always have to rely mainly on itself, or upon its own State weather ser vice. The successful prediction of full fedged tornado is triumph yet to be won by msteorology.