( 242 ) 



Efna, as pofleffing the property of fironglf 

 moving the magnetic needle*, I did not 

 fail to make the fame examination relative 

 to numerous fhoerls of the Phlegrean Fields 

 and EoHan I lies, and can pofitively affirm 

 that I found this quality in them all. It is- 

 at the fame time to be obferved, that I could 

 not perceive it in eleven fpecies of fhoerls, 

 whatever was their colour, fome of which 

 were detached from granites, and others 

 found folitary. This obfervation, w^heii 

 treating of the Euganean mountains, ap- 

 pears to me too important to be omit- 

 ted. 



Thefe Ihoerlaceous lumps or groups, I am 

 of opinion, mud have been produced in the 

 granitous rock by filtration, with this fingle 

 difference, that the quartzofe groups have 

 remained amorphous, and the fhoerlaceous 

 are confufedly cryftallized ; probably from 

 the more ready tendency of the integrant 

 molecules to take a determinate form. 



* See Gliap. VII. 



Havlag 



