The Birmingham age-herald., 1914-05-10
LIGHTNING STRIKES
 TWICE IN SAME SPOT
Old Superstition Has Been
 Proved GrOundless

Lightning is a violent discharge of electricity either between one cloud and another, between a cloud and the earth, or between two strata of air differently electrified, says the Louis Vile Courier Journal. The discharge is commonly assumed to be from a high CT to lower level although it may be from either or both.
 The potential between various air strata or between air strata and the earth is variable, and the changes in it may be sudden. Clear air is, as a rule, electrified positively. and the same is true of air containing smoke, log or falling snow. In rain the elec- trifioation ranges from high negative to high positive, but Is more often pos 1 tive
 l During single storm the air may change back and forth several times from positive to a negative condi- tlon, and the difference In potential l between the earth and a point 10 feet above it may amount to hundreds or | ever thousands of volts. Considering l the surface of the earth as datum the potential increases with elevation, but the difference in potential per unit of vertical distance decreases with all l titude.
 l Two principal kinds of lightning are l distinguished, linear and ball. The ef- fleets of the first may be peculiarly destructive. Its flashes are followed by l thunder and usually accompanied by a seen from great distance, 1t Is called diffused heat, or sheet lightning. The same appearance may, however be due to actually diffused and silent dis charges at great attitudes.
 Results Often Erratic | The same flash may strike and blast | a number Of trees, and the results may l be quite as curious and cratic as the | lightning itself. A tree may be scorched it may be stripped of it's leaves it may be cleft longitudinally, or, more rare- | ly, severed horizontally. Pieces of bark or wood may be torn off in strips. One-ha1f of a trees crown may be wjthered, the other half remaining un- harmed. Sometimes the bark is stripped from only one side, occasionally with out trace of burning; at other times it may be riddled, as by worms. with a multitude of little holes.
 The lightning furrow on a tree Is usually single. but 1t may be double usually in parallel lines. Burrows may he oblique for spiral. the current in such cases following the grain of the new. wood. If the tree is inflammable CT is rendered very dry by the flash a fire may result. In other cases the 1fN duff or humus at the base of the tree is ignited by the flash.
 flash of lightning striking ltp- ward through the tree from its base 9cfs as an explosive. The trees may
 '~-~ tito small fragments and cases have been recorded where these
 piece of hemp. If the
 '., ard flash is less violent the trees may be split radially. The tops of trees have been torn off while the low CT parts remained uninjured. On the other hand, the lower portion of a tree has been demolished while the upper part fell to the ground intact
 In the Same Place
 Lightning often strikes twice or more than twice in the same place Some trees favorably located for attracting the fla sh bear z or 8 scars, all visible, and determined by stem analysts of the trunk. The same is true reearding some rocky summits and buildings Out of 901 recorded by one observer 21 were repeated strokes on trees and buildings
 It has been held. though not proved that the big trees of California are re- peatedly struck by lightning. and that although not killed, their leaders are broken and their tops strnfed in conss- ouence. The form Of their boles and the shape of their crowns would seem to favor this belief. Although giants their heights are much lower than would he expected from the taper of theii boles.
 The effect of lightning on the ground