S52 NORTHERN CHILE. [chap. xvi. 



atmosphere and of the trembling- of the ground : I was much 

 struck by this, when mentioning to some peojDJe at Copiapo that 

 there had been a sharp shock at Coquimbo ; they immediate! v 

 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 earth- 

 quakes, at a period of the year when it is a far greater prodiirv 

 than the earthquake itself; this happened after the shock of 

 i^ovember, 1822, and again in 1829, at Valparaiso; also after 

 that of September, 1833, at Tacna. A person must be some- 

 what 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 ordi- 

 nary 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 foi it, and "almost unprecedented 

 in Central America," it is not difficult to understand that the 

 voliunes of vapour and clouds of aslies 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 baro- 

 meter is low, and when ram might naturally be expected 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 consequently tremble. It is, however, 

 doubtful how far this idea will explain the circunr.stance of 

 torrents of rain falling in the dry season during several days, 

 after an earthquake unaccompanied by an eruption ; such cases 

 seem to bespeak some more intimate connexion between the 

 atmospheric and subterranean regions. 



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

 our steps to tlie house of Don Benito, where I stayed two days 



