CAUSES OF THE WINDS

Manawatu Herald, Volume III, Issue III, 7 January 1890, Page 4

CAUSES OF THE WINDS

earth and its story.) air is heated by contac! ■with the warm earth or iratef ii gradually expands, and consequently, being lighter, expaud<% lifting uj - the denser layer above it, and th«« pro^^ing w a£MDvejrfl^y pat the. top. |ifctjs th^^wr iti a call chiranej would no were it heated by a flrt beneath, and then a lowed to {escape from the end of the shaft 'PredsUw being thus 4in^nish,ed; •■" the. lighter, warm aif 4 s pushed upwards by the iaflovr of the surrounding denser ah at the swfttttA'MAH - r wlhdi may therefore be regarded as due to differences, of < ttfmospheric pressure, ' Ihese differences being assigned to changes jßithar jin» ' teniperatnve or -md' Mniiclity of the air. The wind blows frorji a, region wh^re ,the presstlise4» High; aatl the a r r consequently dense, into, a depression Tvhere tha'^rissrtirdis'low, 'and the air in consequence very thin, that is to say wanting^ •jhm^'d''a stream always tends to the lowest level, the velocity with which; ft qrughes; domi from the height to fill the lake below being proportioned to the steeps ness of the slope— thai is/ to the difference between the IW9 The flow of ,tbje t otniospWe current is exactly analogous — both being due to gravitation. Tims, it two neighbouring; regions ,are,ui^» %<j[Bftyjr« btated.^^hir \^arn\ air from the Ofte,* Tfill >ascerfd'anVl > flow' Vver tho cold ji^ijfc.th^iothier/ -which in its turn wi'l flow in below, infill np 'the space whore there is a deficiency, since, according to the ancient rcaxim, " Nature abhors a vacuum 1 ': Accordingly there will be two cur* rents of air, one blowing, frpm, the warmer to the.'^litetßi Strict in the upper region of the atmosphere, the other comine from the colder ik* the ho ter along the surface of the earth. Th ytj'WWt pc 1 Mied i fiaeb in : mountainous CQuntrijEss, , espec^ftlty- U\ those situated witnin'the warmer zones, the wind wh^re observer stands blowing in a<cUfEer4it^i/ecnori"fr6m the clouds overhead, while aeronauts reckon on returning whence they came by geiting into a different current o^ff^jroffl^^< |^e;Tby r *|wlttfcir i theytwere #af tea upwards. It also often happens that while the air at at ttie surface of tJ}e.esriihi if o^uite calm, the wind is < blowing a gale a few miles above it.