t ««. 3 



talizes in prifms, with four ftriated faces, termi- 

 nated with fharp-pointed pyramids. It deliquefces 

 immediately on expofure to the air. 



A. To water containing this fait, to dete£l 

 the earthy bafis, 



a. Add a little folution of the acid of fugar, 

 the mixture becomes immediately turbid ; the 

 acid of fugar, uniting with the calcareous earth, 

 forms a compound fcarcely foluble in water, 

 which is precipitated, leaving the muriatic acid 

 in the water, as defcribed (page 62, b.) 



b. Add a little of the folution of either of the 

 alkalis^ in a cauftic ftate, white clouds will im- 

 mediately form, the alkali uniting with the muri- 

 atic acid, the calcareous earth is precipitated ; but 

 here, on the liquor being ftirred, the precipitate 

 difappears, for the calcareous earth being in its 

 cauftic ftate fLime) on being mixed with the 

 water, diffolves in it; but if this liquor be ex- 

 pofed to the air, or if fixed air be thrown into 

 it, this lime becomes chalk, which will fall to the 

 bottom. 



c. If the folutions of the alkalis be employ- 

 ed in their mild ftate, or combined with fixed 

 air, white clouds will immediately form, as a- 

 bove, which will difappear again, on ftirring 

 the liquor, but on another principle, there be- 

 ing a double affinity ; for while the alkali com- 

 bines with the muriatic acid, the fixed air, which 

 was combined with the alkali, unites with the 

 calcareous earth, and forms chalk ; but here 

 the fixed air is detached in fuch abundance, 

 as alfo to difiblve the chalk fo formed in the 

 water ; now warm the water, the fuperabundant 



