Intelligence and Miscellaneous Articles. 54 1 



cultly soluble bodies ; this is the case with tartrate of lime, chloride 

 of silver, and the recently precipitated carbonates of nickel and zinc, 

 ^c : but onethatismucb less known is, that recently precipitated car- 

 bonate ot lime does not wholly resist the solvent power of this salt 

 which IS likely to cause error, and lead us to imagine that lime is 

 magnesia in analyses, particularly when the first occurs only in mi- 

 nute quantities. 



Thus when a solution of sulphate of lime is decomposed by an al- 

 kaline carbonate, the precipitated carbonate of lime easily redissolves 

 in a solution of hydrochlorate of ammonia. Again, when very dilute 

 solutions of chloride of calcium and nitrate of 'lime are decomposed 

 by an excess of carbonate of potash, so as to leave no traces of lime 

 in the supernatant liquid, by the addition of a concentrated solution 

 ot this ammoniacal salt the precipitate entirely disappears These 

 clear solutions of carbonate of lime in hydrochlorate of ammonia be- 

 come turbid by exposure to the air, and a portion of carbonate of 

 lime IS again deposited ; but there always remains a certain quantity 

 (lissol-ed which cannot be precipitated even by boiling the clear solu- 

 tion. ° 



h' precipitated carbonate of lime is washed with a sufficient 

 quantity of water, it does not dissolve, after a lapse of twenty-four 

 hours, so easily in the ammoniacal salt as when just precipitated • and 

 even if the precipitate is not washed, but suffered to remain in the 

 Jiquid from which it has been precipitated, its solubility in hydro- 

 chlorate of ammonia, although not prevented, is considerably dimi- 

 nished. 



Even the natural compact varieties of carbonate of lime and the 

 minerals into which it enters, do not completely resist the solvent 

 power of this salt of ammonia. Calcareous spar or Carrara marble 

 finely powdered, and merely shaken for a few minutes with a solution 

 ot this salt, affords a solution, Mhich contains, after filtration, a notable 

 portion of hme. This solubility of carbonate of lime in hydrochlorate 

 ot ammonia is, however, very much less than that of carbonate of 

 magnesia. 



Carbonate of barytes recently precipitated from a dilute solution of 

 the chloride of barium by carbonate of potash, disappears on the addi- 

 tion ot a solution of hydrochlorate of ammonia. This is also partially 

 the ca.se when native carbonate of barytes. in powder, is mixed with 

 a solution of the ammoniacal salt and then filtered : by evaporation 

 of the liquor, a residue is obtained which contains some chloride of 

 barium. The solvent power of sal ammoniac is equally exerted on 

 recently precipitated carbonate of strontia. 



When carbonate of magnesia has been dried at the temperature of 

 boiling water it becomes much more difficult, and takes a much loncer 

 time, to dissolve in the ammoniacal solution than when recently p.eci 

 pitated. The concentrated solution of carbonate of magnesia in hy- 

 drochlorate of ammonia becomes turbid by exposure to air, but does 

 not deposit any magnesia by ebullition. 



At first sight it may seem singular that the earthy carbonates be- 

 fore mentioned should lose their solubility in hydrochlorate of ammonia- 

 Jjut this may be cxjihiincd by admitting that by repose they acquiie 



