302 Mr. Schweitzer on an Analysis of the 



acid, and requires 46H parts of water to re-dissolve it, whereas 

 by the addition of carbonate of soda, the earthy carbonates, 

 hereby produced, do not present any difficulty. For the above 

 quantity of water it was found requisite to add 201*123 grs. 

 of anhydrous carbonate of soda*; the whole was evaporated 

 in a water-bath until a few ounces of fluid remained. It was 

 then placed upon a filter, and the earthy residue A lixiviated 

 with boiling water till the filtered liquor gave no indication 

 of sulphates and chlorides. The fluid obtained from the 

 edulcoration of the earthy residue A was evaporated, when 

 some earthy particles were again separated, which were col- 

 lected upon a filter B. It is here to be noticed, that by this 

 method it is impossible to separate, with any degree of accu- 

 racy, the earthy ingredients from the soluble ones, as, by edul- 

 coration, a small proportion of the former will always be re> 

 dissolved ; and however often this process may be repeated, 

 whereby the quantity of the re-dissolved earthy ingredients 

 will certainly be diminished, still the last traces of them can- 

 not be obtained ; moreover, the repeated evaporation of the 

 lixiviating fluid must carry with it the unavoidable chances of 

 loss : I therefore ascertain these traces of earthy ingredients 

 by themselves along with the soluble salts. A small portion 

 of the earthy carbonates adhered to the sides of the evapora- 

 ting vessel ; these were removed by hydrochloric acid, and the 

 acid solution C, hereby obtained, was left with the other earthy 

 ingredients, A and B, for further examination. 



I. Qjimititative Analysis of the Soluble Ingredients. 



The fluid containing the solubJe salts, and the edulcorating 

 fluids f obtained from the earthy ingredients, were evaporated 

 to the weight of 8100 grs. 



1. ILarthy ingredients, — One-tenth of the fluid (810 grs.) 

 was evaporated to dryness and the residue submitted to various 

 temperatures, when the following results were obtained : — 



At212°Fahr 31*352 grs. 



At 260° to 280° Fahr 31-051 grs. 



Ignited and fused over a spirit-lamp till the 



organic matter was destroyed .... 30*580 grs. 



* By adding the carbonate of soda in solution to the mineral water, it is 

 requisite to ascertain very exactly its quantity in the anhydrous state ; the 

 best method 1 found is to change the carbonate into a sulphate, and to ig- 

 nite the latter in an atmosphere of carbonate of ammonia, so as to dis- 

 charge any possible surplus of sulphuric acid. If the carbonate of soda be 

 ascertained as a carbonate, it must always be fused and quickly weighed. 



f It is always advisable to evaporate first the edulcorating fluids, and 

 when |)roperly concentrated, to mix them with the fluid wiiich chiefly con. 

 tains the dissolved ingredients. 



