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Show 430 NOH.'l'HERN CHILE. June, 1835. cattle and mules can for some time afte~wards find pasture in the mountains. But without snow m the Andes, desolation extends throughout the valley. It is on reco~d, that three times nearly all the inhabitants have been obhged to emigrate to the south. This year there was plenty of water, and every man irrigated his ground as much as. he chose ; but it has frequently been necessary to po~t soldiers at the l · to see that each estate took only Its proper allow-s mces, 11 · · d ance during so many hours in the week. ~he va ~y IS sa1 to contain 12,000 souls, but its produce IS sufficient only for three months in the year ; the rest of the supply being drawn from Valparaiso and the south. B~fore the discovery of the famous silver-mines of ChanunCillo, . Copiap6 was in a rapid state of decay; but n.ow It 1s m a very thriving condition; and the town, whiCh was com-pletely overthrown by an earthquake, has b.een rebuilt. . The valley of Copiap6, forming a ~ere .nbbon of gree.n I.n a desert runs in a very southerly d1rectwn; so that It IS of considerable length to its origin in the Cordillera. The valleys of Guasco and Copiap6 may both be considered. as islands to the northward of Chile, separated by deserts mstead of salt water. Beyond these, there is one other very miserable valley, called Paposo, which contains about 200 people; and then there extends the real desert of Atacama 0 -a barrier far worse than the most turbulent ocean. After staying a few days at Potrero Seco, I proceeded up the valley to the house of Don Benito Cruz, to w~om I ~ad a letter of introduction. I found him most hospitable; mdeed it is impossible to bear too strong testimony to the kindness which travellers receive in almost every part of South America. The next day I hired some mules to take me by the ravine of J olquera into the central Cordillera. On the second night the weather seemed to foretel a storm of snow or rain, and whilst lying in our beds we felt a trifling shock of an earthquake. The connexion between the latter phenomena and the weather has often been a disputed June, 1835. EARTHQUAKES. 431 point : it appears to me to be one of very great interest, and not well understood. Humboldt* has remarked, "It would be difficult for a person, who has lived a long time in New Andalusia, or in the low regions of Peru, to deny that the season, the most to be dreaded from the frequency of earthquakes, is that of the beginning of the rains, which is, however, the time of thunder-storms. The atmosphere, and the state of the surface of the globe, seem to have an influence unknown to us, on the changes produced at great depths." In Northern Chile, from the extreme infrequency of rain, or even of weather foreboding rain, the probability of accidental coincidences between the two phenomena necessarily becomes very small ; yet the inhabitants in that part are most firmly convinced of some connexion between the state of the atmosphere and the tremblings of the ground. I was much struck by this, when mentioning to some people at Copiap6 that there had been a sharp shock at Coquimbo : they immediately cried, " How fortunate ! there will be plenty of pasture there this year." To their minds an earthquake foretold rain, as surely, as rain foretold abundant pasture. Certainly it did so happen that on the very day of the earthquake, that shower of rain fell, which I have described as in ten days producing a thin sprinkling of grass. Mr. Scrope has put forth an ingenious idea, that the period of subterranean disturbance, where the force is just on a balance with the resistance, may be determined by a sudden decrease in atmospheric pressure, which over a wide extent of country might produce a considerable effect. According to this explanation, the earthquake comes on at the given period from that state of the weather, which is generally accompanied by rain. But there is another class of phenomena, where the state of the weather evidently • Personal Narrative, vol. iv., p. 11. In the fourth chapter of the second volume, p. 217, Humboldt, however, appears to think that such connexion is fanciful. |