542 Intellige7ice and Miscellaneous Articles. 



a greater degree of cohesion, and approach the crystalline state, 

 which would naturally diminish their solubility. 



To conclude: the preceding experiments show, 1st, that the solu- 

 bility of an earthy carbonate in hydrochlorate of ammonia will not 

 authorize us to conclude that the precipitate is magnesia ; 'Jnd, that 

 freshly precipitated carbonate of lime, and also both marble and cal- 

 careous spar, are dissolved by this salt ; 3rd, that carbonate of ba- 

 rytes recently precipitated, and also witherite and carbonate of stron- 

 tia, are likewise dissolved by this agent; 4th, and lastly, that the so- 

 lution of the above-mentioned earthy carbonates affords, by its de- 

 composition, carbonate of ammonia and a chloride of tlie base. — 

 L'//2s<i/!<<, Sept.28, 1836, and Jour, fur Prackt. Chimie, No. 7, 1836. 



Note. The importance of the above notice of M. Vogel, in the 

 analysis of those earthy minerals, in the course of which the earth is 

 precipitated from a hydrochloric solution by carbonate of ammonia, 

 has reminded me of some unfinished and hitherto neglected experi- 

 ments which were made in the early part of this year, on the mutual 

 action of hydrochlorate of ammonia and the carbonates of lime, ba- 

 rytes,and strontia ; and as these lead to exactly the same conclusion 

 as that at which M. Vogel has arrived, viz. the mutual decomposition 

 of hydrochlorate of ammonia and the earthy carbonates, I am now in- 

 duced to notice them, as they tend to confirm a fact which must so 

 greatly affect the analysis of many minerals, especially those contain- 

 ing magnesia. 



One equivalent, or .54 grains, of hydrochlorate of ammonia was dis- 

 solved in a ftw ounces of distilled water, and to this solution was added 

 an equivalent, or 98 grains, of perfectly dry carbonate of barytes, 

 obtained by precipitating a solution of the chloride of barium by one 

 of sesquicarbonate of ammonia ; this mixture was then boiled for 

 about four hours, occasionally renewing the water which had been 

 evaporated. During the ebullition, particularly at the commencement, 

 carbonate of ammonia was disengaged, and at the expiration of four 

 hours a perfectly clear solution was procured, consisting of chloride 

 of barium and a trace of hydrochlorate of ammonia, but without the 

 slightest trace of carbonic acid. 



Equivalents of precipitated carbonate of strontia, 74 grains, and 

 hydrochlorate of ammonia, 54 grains, treated in the same manner, 

 were boiled for eight hours : long before the expiration of this time 

 the vapour had ceased to exhibit the slightest traces of carbonate of 

 ammonia; the solution filtered left 3-34 grains of carbonate of strontia 

 undecomposed ; the solution, consisting of chloride of strontium, 

 when boiled with caustic soda, did not afford the slightest indication 

 of ammonia ; it is therefore most probable that the whole of the hy- 

 drochlorate of ammonia in this experiment was decomposed. 



Equivalents of carbonate of lime (precipitated) and hydrochlorate 

 of ammonia, boiled together for eight hours, left -97 grains of carbo- 

 nate of lime, and the solution, when treated with soda, afforded traces 

 of ammonia. 



These experiments not only confirm M. Vogel's conclusion, but they 

 also show that, by an elevation of temperature, the mutual decompo- 

 sing power of these bodies is materially increased ; and it must nowr 



