[ 52 ] 



nearer to the proper end ot our enquiries. Fortunately in this 

 cafe, relatively to the general mode, there neither are nor can be 

 more than two opinions ; if one can be proved falfe" the other 

 mull of neceflity be true. All are agreed that ftony fubflances 

 were originally foft, and even liquid ; but fome think this 

 fluidity was occafioned by their having been diflblved, or at 

 leafl difFufed in water, and afterwards cryflallized, precipitated, 

 or otherwifc feparated from it. This is, at this day, the 

 docflrine moft generally adopted by mineralogifts ; volcanic 

 ftones, by far the leafl numerous of the ftony tribe, forming 

 but a trifling exception to this general facl. 



Lately, however, a very different theory has been offered to 

 the public in the firft volume of the Tranfadlions of Edinburgh, 

 and ably fupported by Doftor Hutton, a gentleman advan- 

 tageoufly known to the philofophic world through an impor- 

 tant meterological difcovery, the General Law of the Formation 

 of Rain. His opinion feemingly refembles, but in fa(fl differs 

 effentially, from thofg entertained by Leibnitz, Telliamed, Moro 

 and'Buffon. They held ftones to have been originally folid, 

 and afterwards liquified by heat j but Dodlor Hutton endea- 

 vours to prove that previous to the prefent ftate of our globe 

 they were utterly deprived of folidity, and have fince acquired 

 it by fufion, and fubfequent congelation on cooling. This 

 fyftem, the moft ingenious certainly that has as yet been 

 devifed, is however but little known or at leaft noticed on 

 the continent ; the few that have mentioned it do not feem to 

 have well comprehended it ; in tiiofe points of view in which 



1 have 



