METHODS OF ANALYSIS. 17 



The authors have, much against their inclination, thought it best to 

 combine the acids and bases in a hypothetical combination to form 

 salts, since the time does not yet seem ripe to abandon this antiquated 

 method of reporting the results of water analyses. That such a com- 

 bination has no basis in fact is doubtless true, since we have every 

 reason to believe that in cases where various acids and basic ions are 

 present in solution no base unites with any one acid to the exclusion 

 of all other acids, or vice versa, but all possible combinations of the 

 various basic and acid ions in solution are formed to some extent. 

 For example, suppose we have calcium bicarbonate in solution. It 

 partly dissociates into its ions as follows: 



Ca(HC0 3 ) 2 ^Ca-h2(H00 3 ) 



Again, if magnesium sulphate is in solution it partly dissociates, as 

 follows: 



If these two solutions are mixed, part of the calcium and sulphuric 

 acid will unite to form calcium sulphate, as follows: 





and part of the magnesium and bicarbonic acid ions will unite to form 

 magnesium bicarbonate, as follows: 



Mg+2(HC0 3 )?Mg(HC0 3 ) s 



so that, in addition to calcium bicarbonate, magnesium sulphate, cal- 

 cium, magnesium, bicarbonic acid, and sulphuric acid ions present at 

 first, there are also calcium sulphate and magnesium bicarbonate in 

 solution. 



In calculating the hypothetical combinations of these acid and basic 

 ions, sodium is joined to nitrous and nitric acid, potassium to iodin 

 and bromin, calcium to phosphoric acid, and sodium to metaboric acid. 

 The residual basic ions are then assigned in the following order 

 ammonium, lithium, potassium, magnesium, calcium, manganese, 

 iron, and aluminum to the residual acid ions in the following order 

 chlorin, sulphuric acid ion, and bicarbonic acid ion. In case the bicar- 

 bonic acid ion is not present in sufficient quantities to join with all 

 the calcium, the residual calcium is joined to silica to form calcium 

 silicate, and manganese, iron, and aluminum are calculated to the 

 oxids Mn 3 O 4 , Fe 2 O 3 , and A1 3 O 3 , respectively. 



DETAILED METHODS OF ANALYSIS. 



The following methods are, to a large extent, the same as those 

 published about three years ago in a Senate document a on the com- 

 position of the hot springs of Arkansas, this investigation having 



Haywood, Report of an analysis of the waters of the hot springs on the Hot 

 Springs Reservation, Hot Springs, Garland County, Ark. Document No. 282, 1902. 



4875 No. 9105 - 2 



