[ ix 3 
logy, with fome alterations of his own ^ how^** 
ever, the principal foundation remained the 
fame in all, or according to Bromelfs method, 
which he had publi&ed in a fmall book, enti- 
tled Indications for the fe arching for Minerals : 
Untii Mr. Pott, a chemift by profeffion, and 
confequently inciined rather to believe the ef. 
fedts of his experiments, than the external ap- 
pearances alone, proceeded farther than was 
cuftomary before his time, in the alTaying of 
ftones by fire, and afterwards publilhed his ac- 
quired knowledge by the title of Lithogeogmfa. 
From this book the faid author received confi- 
derable honour, becaufe the true advantage of 
his refearches began to appear : Miners and 
other manufadturers were by it able to deter- 
mine the reafon of certain effedls, which they 
before either did not obferve, or wilfully con- 
cealed, to avoid the cenfure of being ignorant, 
if they advanced fuch things as real truths, 
which, according to modern fyftems were re- 
garded as contradidtory and abfurd. Mr. Wol- 
terfdorff, a difciple of Mr. Pott, then begun 
immediately to Jorm an e7itire mineral fyjtein^ 
founded upon chemical experiments but his 
mafter did not approve of it, ftill infifting that 
materials were yet w^anting for the purpofe; 
and that every mineral body ought fiifl: to be 
examined and tried with the fame care that he 
had tried and examined the moft fimple of 
them ; to wit, the Earths and Stones. 
Such was, according to the idea I had of it, 
the ftate of Mineralogy, when I, touched by 
the 
