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Show 432 NOR'l'HERN CHILE. June, 1835. appears a consequence (and not the determining. cause) of the eartl 1 quak e. I an ude to those cases, when ram. falls at . d f the year at which it is a greater prodigy than a peno o ' · h the earth quak e I. t se lf.· I may instance the ram after t e shock of November, 1822, at Valparaiso. A person must be somewhat habituated to these climates, to understand the excessive improbability of rain falling at such seaso~s, except as a consequence of some law quite unconnected With the ordinary course of the weather. In the case of great volcanic eruptions, as that of Coseguina, ~here to~~ents ~f rain fell at a time of year most unusual for It, and. almost unprecedented in Central America,"* it is not difficult to understand that the volumes of vapour and clo~ds of ashes, might have disturbed the atmospheric equilibnum. Humboldtt extends this view to the case of earthquakes; but for my part, I cannot conceive it possib~e, that the small quantity of aeriform :fluid which at such times escapes from the fissured ground, can produce such remarkable effects. Humboldtt has stated that, "on the days when the earth is shaken by violent shocks, the regularity of the hor~ry variations of the barometer is not disturbed under the tropics. I have verified this observation at Cumana, at Lima, and at Riobamba; and it is so much the more worthy ~f fixing the attention of natural philosophers, as at St. Dommgo, at the town of Cape Fran9ois, it is asserted, that a wate~ baro~eter§ was observed to sink two inches and a half Immediately • Caldcleugh. Philosoph. Transact. 1835. t Personal Narrative, vol. ii., p. 219. + Ibid., p. 2L7. § Courrejolles, in the Journal de Phys., tome liv ., p. 106. This. depression answers only to two lines of mercury. The barometer remamed motionless at Pignerol, in April, 1808. -(Ibid., t. lxvii., p. 292.) [I may add that the earthquake alluded to by Courrejolles at P· 106, was accompanied b.v a "tres-violent coup de vent;" which explains the :all of his water barometer. More lately, Mr. Williams, in his Narrauve of Missionary Enterprise (p. 442), has given an account of a hurricane which devastated the Austral islands (S. W. of the Society Archipelago), and which at the Navigator Islands was accompanied by an earthquake. -C. D.] June, 1835. ME'l'EOROLOGlCAL I'IIENOMENA. 433 before the earthquake of 1770. In the same manner it is related, that, at the destruction of Oran, a druggist fled with his family, because observing accidentally a few minutes before the earthquake, the height of the mercury in his barometer, he perceived that the column sunk in an extraordinary manner. I know not whether we can give credit to this assertion." Mr. Alison, in a letter dated Valparaiso, informs me, that just before the earthquake of November, 1822, the mercury in the tube of the barometer standing in his store, sank beneath the graduated part. The tube was a bent one; nineteen inches being exposed, and the lowest graduated part corresponded to twenty-six English inches. With this third case, and more especially considering the unquestionable fact of rain so frequently following severe earthquakes, even at the most unusual seasons, I cannot conclude otherwise, than that there exists some connexion between the subterranean and atmospheric disturbances, of which we are at present quite ignorant. Mr. Miers, t in his account of the Valparaiso earthquake, November 19th, l 822, has added one more to the list of coincidences between luminous meteors and earthquakes. He says "one of very considerable size, in apparent dimensions little less than the moon, was observed in the southward, at no very great elevation. It traversed a considerable arch of the heavens, leaving behind it a long train of light; and when it disappeared, it seemed to do so from explosion- as it leaped in the same manner as those which eject meteoric stones ; but in this instance no noise was heard to attend its extinction, nor was it known that any stones fell. This occurred about half-past two o'clock in the morning after the earthquake." The earthquake itself happened at half-past ten o'clock. Mr. Miers then adds, that a friend of his ''travelling on the night of the 4th of November, about a fortnight preceding the great earthquake, observed at a little past eleven o'clock in the northem sky, VOL. III. '~* Miers's Travels, vol. i., p. 395. 2 F |