GENERAL REMARKS ON EARTHQUAKES. 63 



the years 1766 and 1767 the inhabitants encamped 

 in the streets, and they did not begin to rebuild their 

 houses until the earthquakes took place only once 

 in four weeks. These commotions had been pre- 

 ceded by a drought of fifteen months, and were ac- 

 companied and followed by torrents of rain, which 

 swelled the rivers. 



On the 14th December, 1797, more than four-fifths 

 of the city were again entirely destroyed. Previous 

 to this the shocks had been horizontal oscillations ; 

 but the shaking now felt was that of an elevation 

 of the ground, and was attended by a subterraneous 

 noise, like the explosion of a mine at a great depth. 

 The most violent concussion, however, was pre- 

 ceded by a slight undulating motion, so that the in- 

 habitants had time to escape into the streets ; and 

 only a few perished, who had betaken themselves 

 for safety to the churches. Half an hour before the 

 catastrophe, a strong smell of sulphur was expe- 

 rienced near the hill of the convent of St. Francis ; 

 and on the same spot an internal noise, which seemed 

 to pass from S . E . to N. W. , was heard loudest. Flames 

 appeared on the banks of the Manzanares and in the 

 Gulf of Cariaco. In describing this frightful con- 

 vulsion of nature, our author enters upon general 

 views respecting earthquakes, of which a very brief 

 account may be here given. 



The great earthquakes which interrupt the long 

 series of small shocks do not appear to have any 

 stated times at Cumana, as they have occurred at 

 intervals of eighty, of a hundred, and sometimes 

 even of less than thirty years ; whereas, on the 

 coasts of Peru, at Lima, for example, there is, 

 without doubt, a certain degree of regularity in the 

 periodical devastations thereby occasioned. 



It has long been believed at Cumana, Acapulco, 

 and Lima, that there exists a perceptible relation 

 between earthquakes and the state of the atmosphere 

 which precedes these phenomena. On the coasts 



