32 



A HISTORY OF 



which he supposes still deeper, both contri- 

 bute to heave up the earth upon their bosom. 

 This, he thinks, accounts for the lakes of water 

 produced in an earthquake, as well as for the 

 fires that sometimes burst from the earth's 

 surface upon those dreadful occasions. There 

 are others who have supposed that the earth 

 may be itself the cause of its own convulsions. 

 " When," say they, "the root or basis of some 

 large tract is worn away by a fluid under- 

 neath, the earth sinking therein, its weight 

 occasions a tremour of the adjacent parts, 

 sometimes producing a noise, and sometimes 

 an inundation of water." Not to tire the 

 reader with a history of opinions instead of 

 facts, some have ascribed them to electricity, 

 and some to the same causes that produce 

 thunder. 



It would be tedious, therefore, to give all 

 the various opinions that have employed the 

 speculative on this subject. The activity of 

 the internal heat seems alone sufficient to 

 account for every appearance that attends 

 these tremendous irregularities of nature. To 

 conceive this distinctly, let us suppose, at 

 some vast distance under the earth, large 

 quantities of inflammable matter, pyrites, 

 bitumens, and marcasites, disposed, and only 

 waiting tor the aspersion of water, or the hu- 

 midity of the air, to put their fires in motion: 

 at last, this dreadful mixture arrives ; waters 

 find their way into those depths, through the 

 perpendicular fissures ; or air insinuates itself 

 through the same minute apertures: instantly 

 new appearances ensue ;_ those substances, 

 which for ages before lay dormant, now con- 

 ceive new apparent qualities ; they grow hot, 

 produce new air, and ouly want room for ex- 

 pansion. However, the narrow apertures by 

 which the air or water had at first admission, 

 are now closed up ; yet as new air is con- 

 tinually generated, and as the heat every mo- 

 ment gives this air new elasticity, it at length 

 bursts, and -dilates all round; and, in its 

 struggles to get free, throws all above it into 

 similar convulsions. Thus an earthquake is 

 produced, more or less extensive, according 

 to the depth or the greatness of the cause. 



But before we proceed with the causes, let 

 us take a short view of the appearances which 



Plin. lib. ii. cap. 86. 



have attended the most remarkable earth- 

 quakes. By these we shall see how far the 

 theorist corresponds with the historian. The 

 greatest we find in antiquity is that mentioned 

 by Hiny, a in which twelve cities in Asia Mi- 

 nor were swallowed up in one night : lie tells 

 us also of another, near the lake Thrasymene, 

 which was not perceived by the armies of 

 the Carthaginians and Romans, that were 

 then engaged near that lake, although it shook 

 the greatest part of Italy. In another place b 

 he gives the following account of an earth- 

 quake of an extraordinary kind. " When 

 Lucius Marcus and Sextus Julius were con- 

 suls, there appeared a very strange prodigy 

 of the earth, (as I have read in the book of 

 ./Etruscan discipline,) which happened in the 

 province of Mutina. Two mountains shocked 

 against each other, approaching and retir- 

 ing with the most dreadful noise. They, at 

 the same time, and in the midst of the day, 

 appeared to cast forth fire and smoke, while 

 a vast number of Roman knights and travel- 

 lers from the jEmilian Way, stood and con- 

 tinued amazed spectators. Several towns 

 were destroyed by this shock; and all the 

 animals that were near them were killed." 

 In the times of Trajan, the city of Antioch, 

 and a great part of the adjacent country, was 

 buried by an earthquake. About three hun- 

 dred years after, in the times of Justinian, 

 it was once more destroyed, together with 

 forty thousand inhabitants ; and, after an 

 interval of sixty years, the same ill-fated city 

 was a third time overturned, with the loss of 

 not less than sixty thousand souls. In the 

 year 1182, most of the cities of Syria, and 

 the kingdom of Jerusalem, were destroyed 

 by the same accident. In the year 1594, the 

 Italian historians describe an earthquake at 

 Puteoli, which caused the sea to retire two 

 hundred yards from its former bed. 



But one of those most particularly describ- 

 ed in history, is that of the year 1693; the 

 damages of which were chiefly felt in Sicily, 

 but its motion perceived in Germany, France, 

 and England. It extended to a circumfer- 

 ence of two thousand six hundred leagues; 

 chiefly affecting the sea-coast and great riv- 

 ers; more perceivable also upon the nioun- 



b Plin. lib. iii. cap. 85. 



