From ST:R0NTIAN. 17 



With Acid of Arfen'ic . 



41. The arfenic acid difTolves with tardinefs fmall but folid 

 pieces of the foflil. With the artificial carbonate the effervef- 

 cence is lively. In either cafe, the compound continues dif- 

 folved till the acid is almoft faturated, when the liquor grows 

 thick, from the depofition of a white powder, which is the ar- 

 fenicate. A precipitate is formed by pouring Strontitic water 

 on acid of arfenic ; but agitation makes it difappear. This 

 happens till the acid is nearly faturated ; after which the preci- 

 pitate will not be taken up, unlefs upon the addition of fuch a 

 quantity of acid as fliall make it predominate. The arfenic 

 acid being dropped into Strontitic water, a copious precipitate 

 defcends to the bottom, which vaniihes when the acid comes to 

 prevail. 



42. Having diluted a quantity of this acid with about 

 twice its volume of water, I threw into it the artificial carbonate 

 to nearly perfedl faturation. A clear folution refulted, which 

 evaporated on a plate of glafs, gave a gelatinous fubftance, that 

 by longer expofure to the air dried into a white powder. Cry- 

 flalline forms fliowed themfelves on the infide of a glafs, which 

 contained fome of the folution after it had flood for fome time. 

 It is fomewhat curious, and deferving of notice, that this folu- 

 tion lets fall the greater part of the arfenicate it contains as 

 foon as it is made to boil by the application of heat. 



The arfenicate fully neutralized is only in a fmall degree fo- 

 luble in water j an ounce of which, when boiling, takes up ra- 

 ther more than a grain. , 



With Boracic Acid. 



43. To the acid of borax difTolved in hot water, I added a 

 minute portion of artificial carbonate of Strontites ; a flight 



Vol. IV. C effervefcence 



