Permanent Colours of' Opake Bodies. 205 



phlogifticated air, becaufe each of thefe principles 

 confifts of only one of the three ingredients, which 

 are requifite for that purpoie. 



Nor can the recompofuion of calcareous earth 

 be effei5led by phlogifticated air, becaufe it con- 

 tains an excefsofphlogitlon, andadefed of water. 

 Compounds, formed of fuch relative quantities 

 of any of thefe principles, as do not conflitute 

 fixed air, may acquire a due proportion of them, 

 by an addition of the ingredients in which they 

 are deficient. 



Pure dephlogifticated air is reduced to fixed 

 air, by the communication of aqueous, and phlo- 

 giftic vapours, difengaged from bodies, by various 

 modes of decompofition : thefe principles readily 

 combine with air, on account of their great affinity 

 to it. 



Phlogifticated air, when agitated with water, 

 receives into its compofition a quantity of aqueous 

 particles, fufficient to conftitute it fixed air : and 

 by that means, it becomes capable of precipitating 

 lime, from lime water. 



If the analyfis, and recompofition, of calcareous 

 earth be ever fo often repeated, its analyfis will 

 always yield, and its recompofition will always 

 require, the fame relative quantities of air, water, 

 and phlogifton. 



Fixed air therefore, feems to confift of thefe 

 three principles invariably, and conftantly, com- 

 bined in the famQ proportions. 



I {hill 



