PREFACE. xxv 



found " in the feveral volcanos of Italy, 

 France, and Germany; by which the purfuit 

 of tllefe enquiries and enlarged views, for the 

 improvement of fcience and fome of the me- 

 chanical arts, is made eafy and popular. 



Mr. Ferbers account of the Vefuvian lavas 

 alone would give this publication credit. 

 It is not only the firft of that kind, bu 

 may juftly be confidered as a tefl and direc- 

 tion for other countries* which are dellitute 

 of dill-burning volcanos. Probably it will 

 be foon confirmed by the mineralogical ac- 

 counts of Italy of Mr. Guettard, who tra- 

 velled with Perber through a great part of 

 that country ; and, though in fome points 

 he did not entirely agree with him, the 

 public will be the better enabled by his ac- 

 counts to judge of the truth and merit of 

 their refpe&ive opinions. 



From thefe late defcriptions of the Italian 

 and other volcanos, it appears, that there is 

 an unthought-of variety of lavas and volca- 

 nic productions, different in their form, mix- 

 ture, contents^ folidity, nature, ufe, and iitu- 

 ation* We are far, however, from being 

 b 4 acquainted 



