12 HOT SPRINGS, ARKANSAS. 



The constituents determined in each of the 41 hot springs and in the 

 2 cold springs include the following: 



Oxygen, consuming capacity. 



Albuminoid ammonia. 



Free ammonia. 



Lithium. 



Sodium. 



Potassium. 



Magnesium. 



Calcium. 



Iron and aluminum. 



Manganese. 



Arsenic. 



Iodine. 



Bromine. 



Chlorine. 

 Boric acid. 

 Phosphoric acid. 

 Nitric acid. 

 Nitrous acid. 

 Sulphuric acid. 

 Silicic acid. 

 Carbonic acid. 

 Bicarbonic acid. 

 Nitrogen. 

 Oxygen. 



Hydrogen sulphide. 

 Total solids. 



Besides these substances, the following were determined in spring 

 No. 15 (Big Iron), which is not onl} T the largest spring in the group 

 but will serve as an example of all the other springs, since the chemical 

 composition of all of them is so nearly alike: 



Barium. 



Strontium. 



Fluorine. 



Tn reporting the results of analysis, the bases and acids are given in 

 parts per million of the positive and negative ions, except in the case 

 of silica, which, in the present state of our knowledge, we can only 

 report as such, not going into the question of how much is present as 

 the silicic acid ion and how much present as free silica. Iron and 

 aluminum are always reported together, because of the great difficulty 

 in separating such small amounts of the two as appear in these waters. 

 Wherever iron and aluminum are involved in any calculation the 

 whole is considered as iron and given an atomic weight of 56. This 

 is doubtless practically correct, since a test of the residue from a large 

 volume of one of the springs showed that the iron-aluminum precipi- 

 tate consisted almost entirely of iron and contained aluminum, at the 

 most, onty in traces. 



Because of the fact that these analyses will doubtless be referred to 

 by many who have had no chemical training, the author has thought 

 it best to combine the acids and bases in a hypothetical combination, 

 thus reporting them as salts. That such a combination has no basis, 

 in fact, is doubtless true, since we have every reason to believe that 

 where various basic and acid ions are present in solution no base unites 

 with any particular acid to the exclusion of all others, or vice versa, 

 but that all possible combinations are formed, to at least some extent, 

 of the various basic and acid ions present in solution. For example: 

 Suppose we have calcium carbonate in solution. It partly dissociates 

 into the positive and negative ions Ca and C0 3 as follows: 



CaC0 3 — + + + coT 



Again, if magnesium sulphate is in solution it parti}' dissociates as 

 follows: 



MgS0 4 — + + + so7 



Now, if these two solutions are poured into each other, part of the 

 calcium and sulphuric acid ions unite to form calcium sulphate, as 

 follows: 



%i + so~ - caso * 



