HOW LIGHTING IS KINDLED.

Timaru Herald, Volume LIII, Issue 5194, 15 July 1891, Page 3

HOW LIGHTING IS KINDLED.

Tho observations of motoorologißtj show that tho vapour which nßconda m un invisible stato from the ground carrios with it, m calm and fine weather, into tlio higher regions of tho air a vory considerable supply of positive electricity. Enoh minuto particle that goes up hoars its own portion of tho load. When, however, tho invisible vapour haß inountnd into very high regions of tho air, it lonoa its invisibility, and is condented into visiblo mist numerous partioles of tlio aqueous subatanco aro drawn eloao togolher, nnd gruupod into tho form of vesiclos or globuloj. Knob ono of those is then a rosorroir or rocoplablo of electric foroo, und as more and moro watery voaiolos aro condoDscd, mire and moro oloutricity io collectod it, tho guthoring mist i but oaoh of tho water globulos ia still onvoloped by a spaoo of clear air. In a drifting cloud tlio mist, epockscanho discprnod floating ulong lyith transparent, iiitorvulfl between. Tho clear air which lios around tho globulos of yappur than acts as an insulating investiflont ; it imprinnna its own part of tho acquired ulootrioul force m ouch soptmto globule. Tho cloud is thus not. cha.'cod as ft whole, liko a continuous mass of inotul, with its nloctricity spread upon its outer surface It m ituponotratod ovory where with the forco. It is composed of a myriad of electrical spixrku, each Imving its own pnrlioular slmro of thooloctrio forco, and each noting us a cont.ro of eloe.trioa! enorgy on its own account. The electricity which, ut any ouo iiietuut resides m I

the outer surface of a cloud, is, therefore, but a comparatively email portion of that which is present m the entire vapoiou9 mass. That such is the way m which electricity is stored m tho olouda ha» been proved by direct observation. When a gold loaf oleotrometer is placed m the midst of a cloud driven aloDg by the wind, it i» aeen that the etripß of gold leaf continually diverge and collapse as the mass of tbe cloud passes along. There is an electrical charge j acting m all parts, but the charge varies m intensity from place to place acccordingly as there is a greater or less condensation of the particles of vapor m each particular spot. JBut the influence externally exerted by tho cloud is nevertheless capable of being raised to a vary intense degree, because it is, so to j speak, the sum total or outcome of the force contained m the inumerable internal centres I of energy. I

It is no uncommon thfag for the electric • force emanating from a oloud to make itself felt m attractions and repulsions many miles away. Clouds renting upon the remote horizon thus frequently produeo perceptible effectß at distances from which the clouds tbemoelves cai.not be eeen. An electrical cloud banging a mile above the ground acts inductively upou (hat ground with considerable power. When ia Summer time the temperature of the earth's Burfaee m very high, the ground moist, the air calm and the sky clear, very copious suppliesof vapour are steamed up from tl!e ground under the sunshine. Oiouds however, begin at length to gather m elevated regions of the air out of the abundance of Iho supply. The free electricity which htt3 been carried up with the vapour ia at first pretty evenly spread through the clouds ; but after a time, ne Ihe eleotrie charge becomes more and more intenßivo a powerful repulsive force 13 m the end established between th» spherules of the mist, and a very high degree of tension is at last produced at tbe outer surfuce of tho clouds, where it is enveloped by insulating air, until iv the end tbe expuneive energy thore becomes strong enough to occasion an outburst from the cloud. The escape of the redundant charge then appears | to an observer's eye as the flash of lightning issuing from the cloud. Such, ia its simplest form, is tbe way m which lightning ie kindled m the alorm cloud.