* 
58 J. L. Smith on determining the Alkalies in Minerals. 
of which were not as satisfactory as those afforded by the alcohol- 
ether. 
Substitution of Chlorid of Ammonium for Fluorid of Calcium, 
o mix with Carbonate of lime to decompose the silicates. 
48. It was mentioned in the previous paper on this subject how 
carbonate of lime could be rendered as powerful in its decompos- 
ing agency on the silicates as caustic potash, the effect being due 
to the use of some flux, fluorid and chlorid of calcium being used 
for that purpose. I have since tested more carefully the merits of 
the chlorid of calcium, and for various reasons prefer it to the 
exclusion of the fluorid. In the first place it introduces chlorine 
instead of fluorine into the analysis, and secondly, the fusion is 
more easily detached from the crucible, and dissolved by hydro- 
chloric acid. z 
49. The manner of introducing the chlorid of calcium into 
pound it was inconvenient to weigh and mix it with the carbonate 
51. There is no silicate which after having undergone this pro- 
cess, is not easily dissolved by hydrochloric acid. For the action 
of the lime to have been com lete, it is not necessary that the 
mass should have settled down in perfect fusion. The contents 
the crucible are dissolved, and the analysis continued as pointed 
out in 19, 20, 21, &c. 
52. This method insures the obtaining of every particle of the 
processes, and not the least of the advan tages, is the ready method 
of separating all the other ingredients and the small accumulation 
* The chlorid of ammonium is best obtained in a ulverulent condition, by dis- 
solving some of the salt in hot water, and evaporating coals: the omar ett of 
the chlorid of ammonium will deposit itself i i "conditi n, the water is 
— off, and nie salt thrown on bibulous paper, allowed to dry ; the final desicca- 
n being carried on in a water-ba in an y with ssponding 
otter th, or in any other way @ corres 
+ An ordinary portable furnace with a conical sheet-iron cap of from two to three 
mie answer the purpose perfectly well, all the mabe heat being afforded 
