THUNDER AND LIGHTNING.

Mataura Ensign, 13 January 1916, Page 5

THUNDER AND LIGHTNING.

WHAT TO DO. AND AVHAT NOT TO 1)0. Sir Tlay Lankester, in the * Daily Oraphic.' recently gave very practical hints on how to get. struck by lightning, or how not- to, what, to believe, and what to reject, from the confused mass of'popular notions on the subject. There are five different varieties of ''lightning," or visible electrical discharges in our atmosphere—(l) Forked lightning, the familiar and dangorus form ; (2) sheet lightning, w' ich is merely a. reflection of the former on clouds; (.T) St. Klmo's fire, a silent ami continuous discharge oh-orvod at. mastheads on ships or on the tops of mountains: (4) ball lightning, 'or "thunderbolts," destructive but uncommon ; and (;">) the Auroa. I'.orealis. occur! ing only in tlie .Polar regions. Don't, in sei king shelter from an electrical storm, stand under any solitary tree, isolated shed, or lone haystack. Ami don't be a. solitary upstanding mark yourself bv scurrying in tlie open. There is salely in numbers and masses, so that a refuge. Hi the thick woods or under rocks is not lo be despised. Don't- lie alarmed at a terrific thunderclap following a lightning flash alter an interval of two seconds or more. The sound which is caused by heating and sudden expansion of the air by the great electrical spark, is comparatively slow, travelling only at the rate of a mile in five seconds, while the Hash is instantaneous. Therefore, when two seconds or more elapse tlie storm is still at a safe distance of hall' a mile or so. But if the interval between Hash and detonation is only a second or less the electrical disturbance is'close at hand, and any prominent upstanding object in your immediate vicinity is liable to be struck.

Don't expose yourself recklessly with the erroneous idea that the chances against your being struck bv lightning are as a million to one. According to Lankestrian reckoning the chance ot escape for a person facing a violent thunderstorm and taking no precaution is in tlie ration of 10 to one only—not nearly so good as the chance of a soldier in'the front line of battle escaping death or a disabling-wound, nor as the chance of recovery from a "major" surgical operation. Don't imagine that lightning rods are an antiquated ' superstition or a modem "false alarm." On the contrary, competent electricians are occupied in the endeavor to improve- present methods of_ protection by "light-nin-j; conductors.'' Lightning rods placed in high, prominent positions "attract" the electricity from the thunder clouds and conducte it harmlesslv to and underneath the surface of the ground. The solitarv tree or other up'-tandnig object equally attracts the electric spark, but. not being- a good conductor, it. obstructs Ihe passage of the electrical current, which thereupon runs wild, bursting and burning miv living or inert thin--- in its way. There must be no break in the How of the.current from cloud to earth, and nothmn; is more fatal (ban the lightning conductor itself when noi nroperly "earthed."

(Pie widosprc-ad erroneous notion ah.-tit lightning is that it' may "print" ou tlie hodv of the person stuiek a sort oi pic! ure or outline presumably bavin--; some relation to tlie locality or \\hcro ihe event occurred. The only ! piiiid-ition \<>r such an idea is the fact iiiat. tin- branching, tree-like hues an- sometimes found on the skin ol a person struck bv lightning. These are caused bv the dissolving of the- colored corpuscles of the blood in Ihe bloodvessels of the skin where the ligbln'ug ha s .reached it.