meteorology-第14节

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from　being　inhabited　all　round。



　　Now　since　there　must　be　a　region　bearing　the　same　relation　to　the



southern　pole　as　the　place　we　live　in　bears　to　our　pole；　it　will



clearly　correspond　in　the　ordering　of　its　winds　as　well　as　in　other



things。　So　just　as　we　have　a　north　wind　here；　they　must　have　a



corresponding　wind　from　the　antarctic。　This　wind　cannot　reach　us　since



our　own　north　wind　is　like　a　land　breeze　and　does　not　even　reach　the



limits　of　the　region　we　live　in。　The　prevalence　of　north　winds　here　is



due　to　our　lying　near　the　north。　Yet　even　here　they　give　out　and



fail　to　penetrate　far：　in　the　southern　sea　beyond　Libya　east　and



west　winds　are　always　blowing　alternately；　like　north　and　south



winds　with　us。　So　it　is　clear　that　the　south　wind　is　not　the　wind　that



blows　from　the　south　pole。　It　is　neither　that　nor　the　wind　from　the



winter　tropic。　For　symmetry　would　require　another　wind　blowing　from



the　summer　tropic；　which　there　is　not；　since　we　know　that　only　one



wind　blows　from　that　quarter。　So　the　south　wind　clearly　blows　from　the



torrid　region。　Now　the　sun　is　so　near　to　that　region　that　it　has　no



water；　or　snow　which　might　melt　and　cause　Etesiae。　But　because　that



place　is　far　more　extensive　and　open　the　south　wind　is　greater　and



stronger　and　warmer　than　the　north　and　penetrates　farther　to　the　north



than　the　north　wind　does　to　the　south。



　　The　origin　of　these　winds　and　their　relation　to　one　another　has



now　been　explained。







　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　6







　　Let　us　now　explain　the　position　of　the　winds；　their　oppositions；



which　can　blow　simultaneously　with　which；　and　which　cannot；　their



names　and　number；　and　any　other　of　their　affections　that　have　not　been



treated　in　the　'particular　questions'。　What　we　say　about　their



position　must　be　followed　with　the　help　of　the　figure。　For



clearness'　sake　we　have　drawn　the　circle　of　the　horizon；　which　is



round；　but　it　represents　the　zone　in　which　we　live；　for　that　can　be



divided　in　the　same　way。　Let　us　also　begin　by　laying　down　that　those



things　are　locally　contrary　which　are　locally　most　distant　from　one



another；　just　as　things　specifically　most　remote　from　one　another



are　specific　contraries。　Now　things　that　face　one　another　from



opposite　ends　of　a　diameter　are　locally　most　distant　from　one　another。



（See　diagram。）



　　Let　A　be　the　point　where　the　sun　sets　at　the　equinox　and　B；　the



point　opposite；　the　place　where　it　rises　at　the　equinox。　Let　there



be　another　diameter　cutting　this　at　right　angles；　and　let　the　point



H　on　it　be　the　north　and　its　diametrical　opposite　O　the　south。　Let　Z



be　the　rising　of　the　sun　at　the　summer　solstice　and　E　its　setting　at



the　summer　solstice；　D　its　rising　at　the　winter　solstice；　and　G　its



setting　at　the　winter　solstice。　Draw　a　diameter　from　Z　to　G　from　D



to　E。　Then　since　those　things　are　locally　contrary　which　are　most



distant　from　one　another　in　space；　and　points　diametrically　opposite



are　most　distant　from　one　another；　those　winds　must　necessarily　be



contrary　to　one　another　that　blow　from　opposite　ends　of　a　diameter。



　　The　names　of　the　winds　according　to　their　position　are　these。



Zephyrus　is　the　wind　that　blows　from　A；　this　being　the　point　where　the



sun　sets　at　the　equinox。　Its　contrary　is　Apeliotes　blowing　from　B



the　point　where　the　sun　rises　at　the　equinox。　The　wind　blowing　from　H；



the　north；　is　the　true　north　wind；　called　Aparctias：　while　Notus



blowing　from　O　is　its　contrary；　for　this　point　is　the　south　and　O　is



contrary　to　H；　being　diametrically　opposite　to　it。　Caecias　blows



from　Z；　where　the　sun　rises　at　the　summer　solstice。　Its　contrary　is



not　the　wind　blowing　from　E　but　Lips　blowing　from　G。　For　Lips　blows



from　the　point　where　the　sun　sets　at　the　winter　solstice　and　is



diametrically　opposite　to　Caecias：　so　it　is　its　contrary。　Eurus



blows　from　D；　coming　from　the　point　where　the　sun　rises　at　the



winter　solstice。　It　borders　on　Notus；　and　so　we　often　find　that　people



speak　of　'Euro…Noti'。　Its　contrary　is　not　Lips　blowing　from　G　but



the　wind　that　blows　from　E　which　some　call　Argestes；　some　Olympias；



and　some　Sciron。　This　blows　from　the　point　where　the　sun　sets　at　the



summer　solstice；　and　is　the　only　wind　that　is　diametrically　opposite



to　Eurus。　These　are　the　winds　that　are　diametrically　opposite　to　one



another　and　their　contraries。



　　There　are　other　winds　which　have　no　contraries。　The　wind　they　call



Thrascias；　which　lies　between　Argestes　and　Aparctias；　blows　from　I；



and　the　wind　called　Meses；　which　lies　between　Caecias　and　Aparctias；



from　K。　（The　line　IK　nearly　coincides　with　the　ever　visible　circle；



but　not　quite。）　These　winds　have　no　contraries。　Meses　has　not；　or　else



there　would　be　a　wind　blowing　from　the　point　M　which　is



diametrically　opposite。　Thrascias　corresponding　to　the　point　I　has



not；　for　then　there　would　be　a　wind　blowing　from　N；　the　point　which　is



diametrically　opposite。　（But　perhaps　a　local　wind　which　the



inhabitants　of　those　parts　call　Phoenicias　blows　from　that　point。）



　　These　are　the　most　important　and　definite　winds　and　these　their



places。



　　There　are　more　winds　from　the　north　than　from　the　south。　The



reason　for　this　is　that　the　region　in　which　we　live　lies　nearer　to　the



north。　Also；　much　more　water　and　snow　is　pushed　aside　into　this



quarter　because　the　other　lies　under　the　sun　and　its　course。　When　this



thaws　and　soaks　into　the　earth　and　is　exposed　to　the　heat　of　the　sun



and　the　earth　it　necessarily　causes　evaporation　to　rise　in　greater



quantities　and　over　a　greater　space。



　　Of　the　winds　we　have　described　Aparctias　is　the　north　wind　in　the



strict　sense。　Thrascias　and　Meses　are　north　winds　too。　（Caecias　is



half　north　and　half　east。）　South　are　that　which　blows　from　due　south



and　Lips。　East；　the　wind　from　the　rising　of　the　sun　at　the　equinox　and



Eurus。　Phoenicias　is　half　south　and　half　east。　West；　the　wind　from　the



true　west　and　that　called　Argestes。　More　generally　these　winds　are



classified　as　northerly　or　southerly。　The　west　winds　are　counted　as



northerly；　for　they　blow　from　the　place　of　sunset　and　are　therefore



colder；　the　east　winds　as　southerly；　for　they　are　warmer　because



they　blow　from　the　place　of　sunrise。　So　the　distinction　of　cold　and



hot　or　warm　is　the　basis　for　the　division　of　the　winds　into



northerly　and　southerly。　East　winds　are　warmer　than　west　winds　because



the　sun　shines　on　the　east　longer；　whereas　it　leaves　the　west　sooner



and　reaches　it　later。



　　Since　this　is　the　distribution　of　the　winds　it　is　clear　that



contrary　winds　cannot　blow　simultaneously。　They　are　diametrically



opposite　to　one　another　and　one　of　the　two　must　be　overpowered　and



cease。　Winds　that　are　not　diametrically　opposite　to　one　another　may



blow　simultaneously：　for　instance　the　winds　from　Z　and　from　D。　Hence



it　sometimes　happens　that　both　of　them；　though　different　winds　and



blowing　from　different　quarters；　are　favourable　to　sailors　making



for　the　same　point。



　　Contrary　winds　commonly　blow　at　opposite　seasons。　Thus　Caecias　and



in　general　the　winds　north　of　the　summer　solstice　blow　about　the



time　of　the　spring　equinox；　but　about　the　autumn　equinox　Lips；　and



Zephyrus　about　the　summer　solstice；　but　about　the　winter　solstice



Eurus。



　　Aparctias；　Thrascias；　and　Argestes　are　the　winds　that　fall　on　others



most　and　stop　them。　Their　source　is　so　close　to　us　that　they　are



greater　and　stronger　than　other　winds。　They　bring　fair　weather　most　of



all　winds　for　the　same　reason；　for；　blowing　as　they　do；　from　close



at　hand；　they　overpower　the　other　winds　and　stop　them；　they　also



blow　away　the　clouds　that　are　forming　and　leave　a　clear　sky…unless



they　happen　to　be　very　cold。　Then　they　do　not　bring　fair　weather；



but　being　colder　than　they　are　strong　they　condense　the　clouds



before　driving　them　away。



　　Caecias　does　not　bring　fair　weather　because　it　returns　upon



itself。　Hence　the　saying：　'Bringing　it　on　himself　as　Caecias　does



clouds。'



　　When　they　cease；　winds　are　succeeded　by　their　neighbours　in　the



direction　of　the　movement　of　the　sun。　For　an　effect　is　most　apt　to



be　produced　in　the　neighbourhood　of　its　cause；　and　the　cause　of



winds　moves　with　the　sun。



　　Contrary　winds　have　either　the　same　or　contrary　effects。　Thus　Lips



and　Caecias；　sometimes　called　Hellespontias；　are　both　rainy　gestes　and



Eurus　are　dry：　the　latter　being　dry　at　first　and　rainy　afterwards。



Meses　and　Aparctias　are　coldest　and　bring　most　snow。　Aparctias；



Thrascias；　and　Argestes　bring　hail。　Notus；　Zephyrus；　and　Eurus　are



hot。　Caecias　covers　the　sky　with　heavy　clouds；　Lips　with　lighter　ones。



Caecias　does　this　because　it　returns　upon　itself　and　combines　the



qualities　of　Boreas　and　Eurus。　By　being　cold　it　condenses　and



gathers　the　vaporous　air；　and　becaus