206 coSxMos. 



tion ; and fields covered with different kinds of plants found 

 to be displaced in the great earthquake of Riobamba, in the 

 province of Quito, on the 4th of February, 1797, and in that 

 of Calabria, between the 5th of February and the 28th of 

 March, 1783 The phenomenon of the inversion or displace- 

 ment of fields and pieces of land, by which one is made to oc- 

 cupy the place of another, is connected with a translatory mo- 

 tion or penetration of separate terrestrial strata. When I 

 made the plan of the ruined town of Riobamba, one particu- 

 lar spot was pointed out to me, where all the furniture of one 

 house had been found under the ruins of another. The loose 

 earth had evidently moved like a fluid in currents, which must 

 be assumed to have been directed first downward, then hori- 

 zontally, and lastly upward. It was found necessary to ap- 

 peal to the Audie7icia, or Council of Justice, to decide upon 

 the contentions that arose regarding the proprietorship of ob- 

 jects that had been removed to a distance of many hundred 

 toises. 



In countries where earthquakes are comparatively of much 

 less frequent occurrence (as, for instance, in Southern Europe), 

 a very general belief prevails, although unsupported by the 

 authority of inductive reasoning,* that a calm, an oppressive 



* Even in Italy they have begun to observe that earthquakes are un- 

 connected with the state of the weather, that is to say, with the appear- 

 ance of the heavens immediately before the shock. The numerical re- 

 sults of Friedrich Hoffmann {Hinterlassene Werke, bd. ii., 366-375) ex- 

 actly correspond with the experience of the Abbate Sciua of Palermo. 

 I have myself several times observed I'eddish clouds on the day of an 

 earthquake, and shortly before it; on the 4th of November, 1799, I ex- 

 perienced two sharp shocks at the moment of a loud clap of thunder. 

 {Relat. Hist., liv. iv., chap. 10.) The Turin physicist, Vassalli Eandi, 

 observed Volta's electrometer to be strongly agitated during the pro- 

 tracted earthquake oT Pignerol, which lasted from the 2(1 of April to 

 the 17th of May, 1808; Journal de Physique, t. Ixvii., p. 291. But 

 these indications presented by clouds, by modifications of atmospheric 

 electricity, or by calms, can not be regarded as generally or necessarily 

 connected with earthquakes, since in Quito, Peru, and Chili, as well 

 as in Canada and Italy, many earthquakes are observed along with tlie 

 purest and clearest skies, and with the freshest land and sea breezes. 

 But if no meteorological phenomenon indicates the coming earthqunke 

 either on the morning of the shock or a few dnys previously, the iuflii- 

 ence of certain periods of the year (the vernal and autumnal equinoxes), 

 the commencement of the rainy season in the tropics after long drought. 

 and the change of the monsoons (according to general belief), can not 

 6e overlooked, even though the genetic connection of meteorological 

 processes with those going on in the interior of our globe is still envel- 

 oped in obscurity. Numerical inquiries on the distribution of earth- 

 quakes throughout the course of the year, such as tho.se of Von Hoff, 

 Peter Merian, and Filedrich Hoffmann, bear testimony to their frequency 



