From STRONfUN. ii 



With Nitrous Acid. 



\ 



23. When the nitrous acid in its flrongeft flate is poured on 

 a mafs of native carbonate of Strontites, no adlion enfues ; but 

 if fome water be added, the acid commences to adl with ener- 

 gy, and a folution, attended with a briflc effervefcence, is the 

 confequence. Very Uttle will be diflblved, though the fpar be 

 finely powdered, if the acid be highly concentrated. A fmall 

 increafe of temperature, it may be remarked, enables the ftrong 

 acid to attack the folid fpar, and to accomplilh the folution. If 

 you employ an acid previoufly diluted, the ebullition inflantly 

 begins ; for this purpofe, an equal quantity of water at leaft 

 muft be mixed with the acid. If much lefs be added, the ef- 

 fervefcence and folution will commence, but they will both foon 

 ceafe. When the quantity of water is fufEcient, the acid free 

 from adulteration, and the fpar pure, no refiduum is left, and 

 a clear and tranfparent folution is obtained ; but if fomewhat 

 lefs of the water be employed, the fait that is formed by the 

 union of the acid and earth immediately affumes a folid cryftal- 

 line form. It was by a folution carried on in this manner that 

 I procured the moft regular, though by no means the largeft 

 cryftals of this nitrate. 



24. The folution has a ftrong pungent tafte. It is perfedly 

 neutral, and readily by evaporation yields cryftals. Thefe are 

 rarely produced in fo regular a manner that their form can be 

 eafily afcertained. By a flow and fponianeous evaporation, cry- 

 ftals were formed that were hexagonal truncated pyramids. The 

 moft perfedt cryftals, obtained in the way a little ago defcribed, 

 were odlohedral, confifting of two four fided pyramids united 

 by their bafes. Sometimes the apex is truncated, and the cry- 

 ftals terminate like a wedge ; often likewife the angles are trun- 

 cated in different degre'es, which gives a confiderable variety to 

 the fhape of the cryftals, 



B 2 2C. This 



