118 On artificial Carlonate of Lime. 



I precipitated a muriatic solution of pure carbonate of lime 

 with a very pure neutral alkaline carbonate. The deposit 

 was voluminous, and took plkce without effervescence : but 

 having stood for a few minutes on a warm place, a strong 

 disengagement of carbonic acid ensued, and the precipitated 

 carbonate of lime fell to the bottom in a ponderous powder, 

 leaving the fluid clear. It therefore appeared that the cal- 

 careous earth in the moment of precipitation was capable 

 of attracting more carbonic acid than it could a'terwards 

 retain, at the common temperature of the atmosphere. The 

 precipitate, placed on a filler, was washed as k)ng as the 

 percolated liquor appeared to be acted upon by a solution 

 of silver, atid was dried at a heat exceed! ni.';-f- 100% but 

 which nevertheless did not scorch the paper. 



1. Five grammes of this carbonate of lime were poured 

 by small portions into a class phial cfmtaining nitric acid, 

 the weight of which was previously well ascertained. The 

 phial during the solution was kept in a slanting position, 

 so that nothing could be thrown out bv the ef^isrvescence. 

 After a complete dissolution, the mass was gently shook in 

 the phial for a few minutes, to favour the evolution of such 

 carbonic acid gas as might possibly remain in the fluid. 

 The mass had lost 2-18 grains, which, when deducted from 

 5 grains, give 43"6 per cent, carbonic acid. 



2. Five grains of the same carbonate of lime were ignited 

 in a covered plaiina crucible in a small furnace for two 

 hours, by which the mass had lost only 1*53 grains, or 

 30*6 per cent. When afterwards dissolved in nitric acid, 

 it further lost 0*65 grains, or precisely as much as in the 

 preceding experiment. 



3. Displeased with the less favourable result of the latter 

 attempt, I weighed an ignited Hessian crucible, and put in 

 5 grains of the sarne carbonate of lujie. Covered with a 

 close fitting crucible, it was ignited in a furnace for one 

 hour, and was found to have lost 1-7 grain?, or 3 7 per cent, 

 of the weight o<- the mass. It was then exposed for one 



•hour to the .sirongest heat that could be }iiO(luccd in an 

 air furnace, and had on cooling lost 2*i8 grains, or exactly 

 as in the previous instances. 'I'he remaining 2-8'2 grains 

 of lime earth correspond to 56'4 per cent, of the weight 

 of the carbonate of lime. T slacked it with water, whereby 

 it heated much aim fell asuuder, but dissolved thereafter 

 in niiric ?cid, almost in a moruent, without any discover- 

 able sign of hissing, and without any loss of weighl. 



Bucliolz had loimd 43 per cciit. acid and jper cent, 

 water. Did then this \ per cent, escape in niy experiment 



(three 



