1835.] EARTHQUAKES AND WEATHER. 349 



when mentioning to some people at Copiap6 that there had 

 been a sharp shock at Coquimbo : they immediately cried 

 out, " 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' 

 time producing a thin sprinkling of grass. At other times, 

 rain has followed earthquakes, at the period of the year 

 when it is a far greater prodigy than the earthquake itself : 

 this happened after the shock of November, 1822, and again 

 in 1829, at Valparaiso ; also after that of September, 1833, 

 at Tacna. A person must be somewhat habituated to the 

 climate of these countries, to perceive the extreme 

 improbability of rain falling at such seasons, except as a 

 consequence of some law quite unconnected with the 

 ordinary course of the weather. In the cases of great 

 volcanic eruptions, as that of Coseguina, where torrents of 

 rain fell at a time of the year most unusual for it, and 

 "almost unprecedented in Central America," it is not 

 difficult to understand that the volumes of vapour and 

 clouds of ashes might have disturbed the atmospheric 

 equilibrium. Humboldt extends this view to the case of 

 'earthquakes unaccompanied by eruptions ; but I can hardly 

 conceive it possible, that the small quantity of aeriform fluids 

 which then escape from the fissured ground, can produce 

 such remarkable effects. There appears much probability 

 in the view first proposed by Mr. P. Scrope, that when the 

 barometer is low, and when rain might naturally be ex- 

 pected to fall, the diminished pressure of the atmosphere over 

 a wide extent of country might well determine the precise 

 day on which the earth, already stretched to the utmost by 

 the subterranean forces, should yield, crack, and conse- 

 quently tremble. It is, however, doubtful how far this Idea 

 will explain the circumstance of torrents of rain falling In 

 the dry season during several days, aftier an earthquake 

 unaccompanied by an eruption ; such cases seem to bespeak 

 some more intimate connection between the atmospheric 

 and subterranean regions. 



Finding little of interest in this part of the ravine, we 

 K'traced our steps to the house of Don Benito, whore I 

 stayed two days collecting fossil shells and wood. Great 

 prostrate siliciried trunks of trees, embedded in a con- 

 glomerate, were extraordinarily numerous. I measured one 



