Arizona weekly citizen., 1888-03-10
LIGHTNING STRIKES
TO RELIEVE THE ELECTRICAL TEN
 SION OF THE ATMOSPHERE.

The Mys;erioas, Unexpected and Ere
 quentIy Fatal Return stroke'-Wherc
 the Flash Takes Place and why-Con-
 duetiug Carrents-HiGh Houses.
 Now, es a charge of electricity has the
 property of inducing another charge Of
 electricity of an Oppesite kind to itself on
 any conducting" matter near it, and as
 the earth Is composed of what is called
 conducting matter, it follows that a
 charged cloud sailing over the surface of
 the earth induces an opposite charge on
 the ground below. These two opposite charges, one of positive" the other of
 negative" electricity, tend, by another
 well known property of electricity, to rush toward each other and combine. Hence
 when they are able to overcome the resist ance of the air between, which keeps them apart, they leap together with flash and crack, producing the familiar phe- nomena of thunder and lightning.
 Sometimes another cloud floating near the first one takes the place of the earth, and then the lightning Hash takes place between them. Lightning of this kind does not strike the earth; but it might have a destructive effect on the latter for all that, because it might give rise tO the "back stroke, which is sometimes fatal to life. The back stroke" is not due to the direct flash and discharge. It is rather the reaction after the direct dis charge has taken place elsewhere. Sup pose, for example, that a track of upland country, a rural district with trees, farms, and here and there a church dOtting it, is covered by thunder cloud. which induces a charge of electricity upon it. In order that the charge upon the earth may get nearer tO that upon the cloud, so as to combine with it, the electricity, by another well known property, will heap itself on the most prominent and pointed objects of the landscape That is tO say, 1t will ac- cumulate on the trees, barns, chimney tops and spires of the district.
 The whole atmosphere of the region is fin state of tension and suspense. The bolt IS trembling in the balSnce, but no man knows where it will fall Presently there is binding fash of light the sky is rent with lurid stream of fire, and in- stantly the tension is relieved The dis charge has taken place at one point, the point which offers the path of least resist ance through the air, and at which the electric tension was most critical At every other place where the electricity had seriously accumulated, there is con sequently a sudden fall of electric pOten- tial. or a collapse to its old condition. or as it is called, return stroke" This | chaI>ge is sometimes as 1 fatal as the direct discharge, and it may 1 ruin a building or destroy life several | miles from the scene of the flash. The | return stroke is therefore more my 'eriOus | and unexpected than the flash, but fatal | af Tv- Nevertheless, since the latter have been | attributed tO this cause, a person cannot | feel quite safe, although a thunder storm | with lightning is still several miles from | him; the number of miles being estimated by counting the seconds which elapse be- tween the flash and the peal, and allow Ing a distance of four miles for every second counted. He may feel safer than f 1t were close upon him, but there is still 'Ome room for fear.
 In fact there Is no real safety eycept within the area properly protected by lightning conductor, or in a building l which is itself a protector, for instance a Iheet iron house. Every building. then. hOuld be protected in order to be safe. h the country, where these are often solated, lightning rod would be required or each; but in towns one rod would ometimes protect more than one house round 1t, according to it's height and con uctvity. The flash takes place at the point of east resistance, because it is here that the | wo opposite electricities can easiest rush ogether. But the eagerneSs with which | hey tend to rush together is another hing to be considered. These two things sken together determine the discharge here may be less resistance to the flash one house or tree than at another, but
 the attraction between the opposite ectrtcities is less at the former, the flash lay traverse the latter house. Hence E ne cannot exactly say if one tree or il hiding will be safer than another. There T great uncertainty, and this is a reason IT the instinct of awe and uneasiness i hich most animals feel on the approach \ thunder storm. si In general, however, we can say that SSi gh houses, or those perched on high ~' 'ound, are more likely to suffer from the scharge than small low lying houses. he former are therefore all the more eli ole for protection; and they are to be 'oided in seeking shelter from a storm. are houses surrounded by trees. and lth ponds or pools of water close beside em- For trees act as imperfect light ng rods, having good earth connection. d especially if they are wet the dis a arge may strike the house in order to | ach the ground through them, or, in the - SC of the pond, through the water. One l l ould not shelter under trees of any | = nd, but more especially tall, soft trees D e poplars- Many deaths have been in St rred from sheltering under poplar trees France. A Thunder storms are said to be rno-e 'quent Tn open, treeless countries. such the Transvaal or the Scottish hills. md Tact has been attributed to the un- ecked ascent of electrical vapors, but the other hand they are probably less 'tructive in such countries.
 Ihimneys, by creating currents of warm oke and by their lining of conducting t, are dangerous parts of houses. and re are many instances of the discharge lng that road It were better, then, to 'ld sitting near a fire in a storm. In 'd, the safest place in the house on such occasion would seem to be in the cellar l basement rooms or upon an iron bed Ad- In the open air there cannot be a CT place than dry hole or ditch. for it ces the body below the surface of tbe und, and therefore not exposed on A minent place. But it should be, a dry low, else the water in it may invite the r ,harge; for water, being a conductor fin tef d connection with the earth. lowers req resistance tO the discharge. e.-Enciucer- H.r
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 Brnzil's Diamond Mines Co |,