THE MINERAL SPRINGS OF SARATOGA 39 



the northern part of the village. As the strength in salt and the total 

 grains per gallon have diminished in later years, the relative amount 

 of calcium bicarbonate has increased. This salt is always available 

 for the carbonated waters to dissolve from the limestone. One 

 would anticipate the same relation for the magnesium bicarbonate 

 but in the high percentages of the table, it seems difficult to establish 

 them. The magnesium salt is generally less than the lime, but in the 

 six percentages of 20 and above, five exceed the lime salt, and one 

 of the Congress' 1843, is almost equal. 



In the values of NaHCOg above the superior limit of the general 

 range, there are six, respectively: 22.4, 22.9, 25.2, 29.1, 33.0, and 67.3. 

 All the other fifty-seven analyses (in three NaHCOs is not reported) 

 run less than 15 ; forty-seven of them less than 10. The high values 

 may be regarded in a questioning spirit. 



In ten analyses no KCl is reported. Fifty-two others are less 

 than 5. The three remaining are 6.8, 9.8 and 11. 2. 



These analyses are of interest when compared with those recorded 

 for sea water on a subsequent page. 



THE CARBON DIOXID 



This gas is one of the most important features of the waters and 

 is what gives them their palatable taste. Before undertaking its 

 discussion a few fundamental properties of it may be recorded in 

 order to make the subsequent statements intelligible. We have to 

 distinguish between the uncombined (free) carbon dioxid and the 

 portion combined with the bases as bicarbonates. 



The combined portion remains in solution and is not apparent to 

 general observation. The uncombined is also in solution in the 

 depths of the earth, having formed with water, HgO, carbonic acid, 

 H2CO3, but as the water rises to the surface, this weak acid under 

 the influence of diminishing pressures breaks up again into HoO 

 and CO2. The gas escaping causes the effervescence or ebullition, 

 as the case may be. Not all of it escapes because under the ordi- 

 nary surface conditions the water retains in solution an amount of 

 gas equivalent to its volume. That is, the water dissolves one 

 volume of the gas. While the presence of the NaCl has some effect 

 on the solubility of the COo, yet it is not enough seriously to influ- 

 ence the relations. The one volume of the gas which normally 

 remains in solution can be driven off by boiling, or can be freed in 

 a vacuum. 



