4 3fmpetfetttott of tt>e <£&pmitt'£ 



Principles , I fuppofe it may both keep 

 my opinion from appearing too pre- 

 sumptuous, and (which is far more 

 confiderabte) may make way for the 

 fairer Reception of the Mechanical 

 Hypothefis about Qualities, if I here 

 intimate (though but briery and in 

 general) fome of thofe defects, that 

 I haveobferved in Chymifts Explica- 

 tions of Qualities. 



And I might begin with taking no- 

 tice of the Obfcurity of thofe Prin- 

 ciples, which is no fmall defect in 

 Notions whofe proper officelt fliould 

 be to conduce to the illuftration of 

 others. For, how can that facilitate 

 the under ftanding of an obfeurd 

 Quality or Phenomenon which is it 

 felf fcarcely intelligible, or at leaft 

 needs almoft as much explanation as 

 the thing 'tis defigned & pretended 

 to explicate ? Now a man need not 

 fre very cenverfant in the writings 

 ofChymiitstoobferve,in how Laxe, 

 Indefinite, and almoft Arbitrary Sen- 

 fes they employ the Terms of Salt s 

 Sutykur and Mercury 5 of which I 

 •••■'.' ' could 



