Skey. — On the Solubiliti/ of Calcic Carbonate in Alkaline Chlorides. 451 



5. — Solid carbonate of lime (as limestone) having been placed in contact 

 for twenty-four hours with a cold aqueous solution of an alkaline chloride 

 was found to be dissolved to a far greater extent than it would have been 

 by the same volume of pure water, and further, the saline solution of lime 

 thus made rapidly deposited a very considerable portion of this earth when 

 heated to about 180° Fahr. Carbonate of soda was found to have the same 

 effect upon limestone as sodic chloride. 



The results of the first two experiments clearly show the solvent effects 

 of strong solutions of several saline substances upon bi-carbonate of lime as 

 newly made. The results of experiments Nos. 3 and 4 show that a naturally 

 hard water when charged to only a comparatively small extent with sodic 

 chloride refuses to part mtli any of its lime when treated with Clarke's 

 process ; they show further a certain extent to which this retention of lime 

 may occur, a matter which will be fally considered shortly. 



The results of the last experiment are confirmatory of much which has 

 been stated before, by demonstrating the fact that cold aqueous solutions of 

 an alkaline chloride or carbonate can dissolve the solid carbonate of lime, and 

 that high temperatures are inimical to the retention of the dissolved earth 

 by such solutions. Where necessary the solutions were boiled prior to use 

 in order to expel any carbonic acid present. 



I should state here that the common test for lime — oxalate of ammonia — 

 could not be successfully used in examining for lime in experiment No. 5, 

 as oxalate of lime is also very sensibly soluble in salts generally ; this 

 manifested itself to me very early in these experiments, by the fact that 

 water containing a trace of sodic carbonate but otherwise pure, after being 

 boiled with limestone and treated with this oxalate, afforded no reaction 

 of lime, although this body was proved to be present in quantity sufficient 

 to afford a good indication with the oxalate were the soda absent. This 

 salt is, indeed, very similar to the bi-carbonate in respect to solubility 

 in saline solutions. 



Of all the salts tested for a solvent property of this kind the fixed alkaline 

 carbonates appear to possess it to the largest extent. 



The greater solvency of calcic carbonate in cold solutions of certain salts 

 is an interesting fact and one about which the following particulars should 

 be given. The finely powdered calcic carbonate was digested with a solution 

 of the salt (first previously boiled for twenty-four hours) at a common tem- 

 perature in a vessel closed from the air. The solution rapidly filtered off, 

 afi'ording a very perceptible precipitate when treated with oxalate of ammonia, 

 and a still greater precipitate when slightly warmed. Another portion of 

 the calcic carbonate was digested for the same time in hot solution of the 

 alkaline carbonate, but the liquor gave no precipitate with oxalate of 



