EARTHQUAKE. 



bas been placed within it by the wisdom 

 of the Creator, an idea not of more doubt- 

 ful evidence than the existence of the 

 electric fluid invisible, or any other of the 

 phenomena of nature by which we are 

 surrounded. (See VOLCANO). Admit- 

 ting tli esc premises, another cause of 

 earthquakes occurs ; it is well known, 

 that volcanos communicate with the sea, 

 by the frequent discharge of saline wa- 

 ter and tufa, or the slime and mud of its 

 bottom through their craters ; this inter- 

 fering with the operations of the fire, vast 

 bodies of steam must ensue, than which 

 nothing can be more powerful and insi- 

 nuating; this rushing by the force of vio- 

 lent explosions through every aperture 

 of the various strntas of the surrounding 

 earth, must occasion those horizontal and 

 perpendicular movements and tremblings, 

 so terrific to the inhabitants above ; be- 

 sides, hot steams impregnated with 

 sulphurous vapours often attend earth- 

 quakes. 



Homer, whose knowledge was exten- 

 sive, seems to have been aware that the 

 sea caused earthquakes, several instances 

 of which might be quoted from the 

 Iliad : 



"But Neptune rising from the seas 



profound, 

 The God whose earthquakes rock the 



solid ground." Book xiii. 1. 67. 



And in the xxth book, line 77. 



" Beneath, stern Neptune shakes the 



solid ground ; 

 The forests wave, the mountains nod 



around ; 

 Through all their summits tremble Ida's 



woods, 

 And from their sources boil her hundred 



floods." 



Indeed the sudden eruption of stones 

 and calcined matter seem unquestionably 

 the effect of water flying off in steam, and 

 carrying every loose object with it. The 

 sea, or water of any great extent, always 

 indicates the commencement of an earth- 

 quake before it is otherwise perceived ; 

 this circumstance dyth not proceed from 

 any cause peculiar to the component parts 

 of the water, but merely from the motion 

 of the e-irlh under the bottom, which is 

 not felt by u person on the adjacent shore, 

 probably from its gliding steadily in one 

 direction, and returning in the same man- 

 ner ; but water, ever seeking a level, will 

 rise at the remotest influence from the 



land, as that inclines towards it, and 

 then rush precipitately back to its pre- 

 vious level, as far as it can be attained, 

 before another inclination of the earth 

 prevents it. The sea is observed to re- 

 tire before the eruptions of Vesuvius, 

 which is evidently caused by the ris- 

 ing of the earth during the first efforts 

 of the matter endeavouring to escape 

 out of the mountain ; when that is dis- 

 charged, the w?ter flows back again im- 

 petuously, plainly indicating that the 

 earth has again sunk to its original place ; 

 the same effect was noticed at Lisbon, 

 as far as related to the dreadful agita- 

 tion of the sea, from which vessels re- 

 ceived violent shocks at fifty leagues 

 distance ; indeed the effects of that earth- 

 quake, so fatal to the city above named 

 in 1755, were felt throughout Europe and 

 America. 



Having detailed some of the probable 

 causes of earthquakes, it will be pro- 

 per to mention the indications of their 

 approach in those countries where they 

 are most prevalent, which is in Mexico, 

 Peru, Jamaica, and the neighbouring 

 islands ; Italy, particularly in Sicily, Asia 

 Minor, and Portugal ; they are felt in al- 

 most every other country, but so slightly 

 as seldom to occasion serious injury: Be- 

 ginning near their visible causes, where 

 they are necessarily most frequent, it 

 may be observed, that when a long inter- 

 val has occurred from the last eruption 

 of a volcano, there is just reason for alarm, 

 that the succeeding will be introduced by 

 violent concussions of the earth. There 

 are some phenomena which attend earth- 

 quakes of decided certainty, others may 

 happen accidentally near the time of their 

 approach, and lie attributed erroneously 

 to them ; such as very dry and hot sea- 

 sons, which undoubtedly take place fre- 

 quently where shocks are but little 

 known, and dark atmospheres caused by 

 unusual vapours ; of the latter, many in- 

 stances are recorded without the least 

 calamity following ; indeed the case of 

 Lisbon is directly in point against this be- 

 ing universally an indication of earthquake, 

 for the morning of that dreadful day was 

 particularly fine, and the sun shone with 

 the utmost brilliancy. Xeither is the sud- 

 den ebbing and flowing of the sea, or 

 rivers always to be depended upon as 

 the forerunner of convulsions of the earth, 

 though it is uniformly the consequence of 

 them, as such effects have been observed 

 without any assignable cause. Electrical 

 phenomena sometimes attend them, in vi- 

 olent streams of lightning, the aurora 



