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Show 216 ' HALCYON DAYS. When the thunder-storm is followed by fine weather, it is said, in common language, that "the thunder clears the air;" but though the fine weather follows the thunder, it is no more the cause of th~t fine weather than the battle in which one party ~s vanquished is the cause of peace. The thunder IS the battle the resistance made by the bad weather in opposi1;g the good ; and the good wea_ther ta~es possession of the atmosphere only after 1t has van-quished and driven off the bad. . When the bad weather invades any place m a thunder-storm, the appetlrance_ is often _very grand. The wind may have be ell blowmg stead1~y from. the same point for weeks; and. som~ peculiarly br_Ight day (for the first sign of an mvaswn o~ the honzon is commonly unusual ~right~1ess) the wmd mar keep its point all the mornmg, till about twelve o cloc~, without a particle of curl-cloud, or any one suspicious appearance, save the unusual fineness of the day and purity of the air. Now although those treacherous davs were known and named "halcyon days," by the ancients, and are still well ~?own to ·the northern fishermen by the name of weather glUts," that is, worn, weak, or cracked parts o_f the weather, yet they are not much heeded by ordmary observers. Well, about twelve or one, on one of these days, when it is delightful_ly clear, and at the same time most intensely hot, m consequ~nce of there being no evaporation to ?ool the mr ; ~nd when, in consequence of there bemg n? evaporation, the leaves do not languish, as they do m a dry atmo4 sphere; a little cloud, wit~ an edge ~s well defined as if It were a perfec~ sol~d, makes .1ts appeara_nce in the point of the honzon J~lst oppos!te to the wmd. If it happen to be i~ t~e pomt opposite the su~ to?, and in some places 1t IS generally fr.om that pomt, It is at first as white as snow, and might p~ss for_the summit of a distant snowy ridge. There IS _no_ light cloud strewing before it, as there generally IS m the MARCH OF THE THUNDER-CLOUD. 217 case of those clouds that ride quietlv on "their own wind." Its whiteness is a proof o( its density· for it shows that it has body enough to reflect the e;1tire light of the sun, and so the shady side of it will be a~ black as the sunny side is white. [It is the same kmd of treacherous appearance which we have in the white curl-clouds,-:-they are white, not because they are rare, but because they are dense and the whiter the denser.] ' ~he firm outline is occasioned by the resistance whtch the cloud e~counters, and the pressing of it between the two wmds would brino- it down in rain only that the opposing wind blows l:lunder it, and th~ heat of that and of the earth repels it upwards. The top projects the most, but both that and the under side are turned back in a sort of head like that of a streamlet when it rolls before it a stone which its force ~an barely roll, and no more ; so that, long before_ It reaches the zenith, there is a deep shade upo!l 1t, all but the front edge, which, as it pushes on m curved scallops, shows white sometimes on one, and sometimes on another. When its edo-e is about_ the z~n~th, it appears to move with grgater veloctty, as It IS then nearest to the eye. As it approaches t~e place of the sun, the edge becomes very splendid; and as there are places which admit only the red rays of the sun and the heating rays to pass through, some of the tints are dismal. The red li&"ht through the thinner parts of the cloud, mingling w1th the reflected green from the earth, o-ives !he cloud and the air under it a very smoulde~ino- and murky appearance, as if the sky were about ~to be on fire. If the cloud is to break where the observer is, the lightning usually begins about that stao-e · the first ~ashes being in the cloud, that is, thro~gh the dry atr that separates the different strata and the thunder is low and growling. But every fl~sh brino-s some of the strata together, and the collected ma~s descends towards the earTth with increasing velocity·, |