ON A NATURAL SYSTEM 



dies, charged with inflammability, and to which 

 principle foflils perhaps arc indebted for their 

 exiilence. Earths and metals, according to their 

 character, hold with propriety a middle (la- 

 don. 



j XL vi i. Di/lingui/hlng Marks of each Clafs. 



FOR the prefent it may be fufficient to men- 

 tion the following criteria of the clafles, which 

 fhall afterwards be more fully explained. 



Salts very finely pulvcrifed, and diflolved in 

 a thoufand times their weight of water, are more 

 or lefs fendble to the talle. With rcfpcdl to 

 diflilled -'water 2 is the common limit of their 

 fpecific gravity. 



Earths have neither taflc norfolubility. They 

 are however taken up by proper fun pie falts. 

 Though for the moll part heavier than falts, 

 they are not reducible to a metallic Aale. When 

 compared with water, their fpecific gravity 

 iluduates between 3 and 4;, which it has never 

 yet exceeded. 



Metals arc not foluble in water; have a pecu- 

 liar fplendour; and furpafs all other known bo- 

 dies in fpecific gravity. They are at lead fix 

 times heavier than equal bulks of water, com- 

 monly much more ; but never exceeding twen- 

 ty times. 



Fhlojjiflic bodies are almoft always lighter 



than 



