116 MR. E. SCHUNCK ON THE ACTION OF 



Through the filtered liquid, which is much lighter in colour 

 than before, I now pass a stream of carbonic acid gas, until 

 the excess of lime is completely neutralized, after which it is 

 evaporated almost to dryness. The carbonate of lime which 

 is deposited during evaporation is separated by filtration, and 

 the liquid is evaporated with the addition of an excess of 

 muriatic acid, until it leaves a thick dark brown syrup. In 

 this syrup there is formed, after cooling and standing, a mass 

 of crystals. These crystals must now be strongly pressed 

 between folds of blotting paper, until the whole of the syrupy 

 mother liquor containing chloride of calcium and other impu- 

 rities has been absorbed. The crystalline mass left on the 

 paper, which has a light brown colour, is now treated with 

 boiling alcohol, which leaves undissolved a quantity of sul- 

 phate of lime. The alcohol, after filtration, is evaporated to 

 dryness, the residue is re-dissolved in boiling water, and the 

 solution is decolourized with animal charcoal. The solution 

 now leaves on evaporation to dryness a colourless crystalline 

 mass, consisting partly of needles and plates, partly of crystal- 

 line crusts. Now this crystalline mass is found to possess 

 the properties of an acid in a very marked manner. Its taste 

 is at first strongly acid, but this is immediately followed by a 

 nauseous, somewhat metallic after-taste. Its solutions redden 

 litmus paper strongly. When heated on platinum foil it 

 melts and burns with a very pale flame, leaving a slight car- 

 bonaceous residue. When heated in a glass tube it melts, 

 and crystallizes again on cooling. When further heated it is 

 volatilized, yielding fumes which strongly affect the nostrils 

 and throat, produce a choking sensation, and excite violent 

 coughing. The fumes condense on the colder parts of the 

 tube, partly in the shape of needles, partly as a white, 

 crystalline, radiated mass. Very little carbonaceous residue 

 is left, and even this is probably due to impurities, so that 

 the acid may be considered as completely volatile. The 

 watery solution of the acid gives the following reactions. 



