[ xi 1 



advantage, when more knowledge in that matted 

 is obtained : But thus much we certainly know 

 by experience, that the mineral kingdom is ex- 

 tremely well adapted to be examined by theie 

 means. The experiments made by, the inge- 

 nious Mr. Romberg, with Tfchirnhauien's 

 burning-glafs, may certainly be carried yet 

 farther, whereby lome doubts may like wife be 

 removed, which flill remain regarding fome of 

 the effects oi his experiments. Thus, we 

 fhould be employed in obferving the pheno- 

 mena and drawing conclufions from them, in- 

 fread of only fearching for the principles of 

 thofe effects, as naturalifts were formerly obliged 

 to do. 



How fatisfied would every lover of fyftems 

 be, if by this means he could get materials 

 properly prepared to compofe a better work, ia 

 which he could introduce the few valuable 

 things which are to be found among the old 

 ruins, and leave out all the vague exprtffions^ 

 together with the diminutions, that are of no 

 confequence. 



When I had, for the above-mentioned pur- 

 pofe, collected my o .-. n obfervatiofrs, and thofe 

 of others, I heard of two new books on the 

 fame lubjecl , they were Mr. D Arg^nville^ 

 Oryclology, and Mt Jufti's Mineralogy; for 

 which reafon i la d my rnanuicr.pt aiide, un- 

 til I had, by the eru.-al of thofe t.vo works, 

 convinced myiell that tbofe gentlemen had not 

 prevented me from purfuing my ilan ; for, 

 the former has, ia my opinion, endeavoured to 



brinpf 



