t 32 j 



of filver, left the filver be precipitated by a cal- 

 careous earth, which may be in the water. 



III. EARTHY SUBSTANCES; 



a. Calcareous earth, or calcined lime-stone^ 

 is found in moil wells and medicinal fprings 

 the prefence of which is belt difcovered by a 

 folution of lead in the nitrous acid. This acid 

 mould be fatu rated with as much lead as it will 

 dirTolve, left the fuperfruous acid mould fatu- 

 rate «the earth, and prevent the precipitation of 

 the lead. If there be any calcareous earth in 

 the water, this folution turns it milky, and after 

 fome time a white powder is depofited, the cal- 

 careous earth precipitating the lead, by uniting 

 with the nitrous acid. 



b. If calcareous earth be fufpended in water by 

 combination with the vitriolic acid, gypfum, or 

 felenites, is formed, which may be difcovered 

 by the addition of alkaline fait to this com- 

 pound ^ the mixture mould be warmed a little, 

 to promote the precipitation of the felenitic 

 earth. 



c. The fame acid united with argillaceous earth, 

 or earth of alum, produces an aluminous auftere 

 composition and the earth may be precipitated 

 alio by alkaline fait, which uniting with the vitri- 

 olic acid, allows the earth to fall down in a 

 fediment. 



IV. SULPHUREOUS. 



Sulphur may be fufpended in its proper 

 form, though it is not foiuble in thisftatej but 

 when the principle of inflammability in fulphnr 



is 



