xviii PREFACE. 



2. The earthquakes and volcanos, being 

 the chief vifible and powerful caufes of the 

 inequalities and fhattered condition of the 

 furface of the earth, fhould long ago have 

 engaged the philofophers to enquire into 

 their nature and effects. Hypothetical theo- 

 ries we have in abundance ; nay, we may 

 at leifure hours in our clofets very eafily 

 invent new ones, without improving fci- 

 ence. But have we facls enough, well exa- 

 mined and well defcribed? Have we clofely 

 attended to their various effects and circum^ 

 frances? Did we make fair allowances for* 

 them, when we attempted to apply them to 

 our orological fyftems ? Had we from juft ob- 

 fervations abftracted infallible characters, by 

 which we were enabled to difcover their for- 

 mer deftructions and creations, in thofe parts 

 where hiftory left us in darknefs? Surely 

 not! 



Mr. La Con&amlne fairly acknowledges, 

 that he and his fellow academicians were un- " 

 acquainted with the volcanic productions, 

 when they were fent to Peru, and frequently 

 encamped for weeks and months on Pi- 



chincha, 



