210 COSMOS 



description of it from the report of many witnesses, and from 

 the documents of the municipahty, of which I was allowed to 

 make use. From the 13th to the 16th of January, it seemed 

 to the inhabitants as if heavy clouds lay beneath their feet, 

 from which issued alternate slow rolling sounds and short, 

 quick claps of thunder. The noise abated as gradually as it 

 had begun. It was limited to a small space, and was not 

 heard in a basaltic district at the distance of a few miles. 

 Almost all the inhabitants, in terror, left the city, in which 

 large masses of silver ingots were stored ; but the most cour- 

 ageous, and those more accustomed to subterranean thunder, 

 soon returned, in order to drive off the bands of robbers who 

 had attempted to possess themselves of the treasures of the 

 city. Neither on the surface of the earth, nor in mines 1600 

 feet in depth, was the slightest shock to be perceived. No 

 similar noise had ever before been heard on the elevated table- 

 land of Mexico, nor has this terrific phenomenon since occurred 

 there. Thus clefts are opened or closed in the interior of the 

 earth, by which waves of sound penetrate to us or are impeded 

 in their propagation. # 



The activity of an igneous mountain, however terrific and 

 picturesque the spectacle may be which it presents to our con- 

 templation, is always limited to a very small space. It is far 

 otherwise with earthquakes, which, although scarcely per- 

 ceptible to the eye, nevertheless simultaneously propagate their 

 waves to a distance of many thousand miles. The great 

 earthquake which destroyed the city of Lisbon on the 1st of 

 November, 1755, and whose effects were so admirably investi- 

 gated by the distinguished philosopher Emmanuel Kant, was 

 felt in the Alps, on the coast of Sweden, in the Antilles, An- 

 tigua, Barbadoes, and Martinique ; in the great Canadian 

 Lakes, in Thuringia, in the flat country of Northern Ger- 

 many, and in the small inland lakes on the shores of the Bal- 

 tic.^ Remote springs were interrupted in their flow, a phe- 

 nomenon attending earthquakes which had been noticed among 

 the ancients by Demetrius the Callatian. The hot springs of 

 Tophtz dried up, and returned, inundating every thing around, 

 and having their waters colored with iron ocher. In Cadiz 



* [It has been computed, that the shock of this earthquake pervaded 

 an area of 700,000 miles, or the twelfth part of the circumference of the 

 globe. This dreadful shock lasted only five minutes: it happened about 

 nine o'clock in the morning of the Feast of All Saints, when almost the 

 whole population was within the churches, owing to which circum- 

 stance no less than 30,000 persons perished by the fall of these edificea^. 

 Bee DaubeneyOn Volcanoes, p. 514-517.] — Tr 



