506 



A. C. LANE MINE WATERS AND THEIR FIELD ASSAY 



COj and SO3, and, excejot in very granitic countries or arid regions, lime 

 and magnesia are the leading bases. The total solids are not commonly 

 over an ounce per cubic foot (1,000 per 1,000,000) and saturation with 

 bicarbonates (=238 per million CaCOa) seems to be a very common 

 goal. The specific gravity is not markedly greater than that of pure 

 water (is not > 1.000). 



Analyses of such waters abound. They are the daily Avork of Leigh- 

 ton's division of the IT. S. Geological Survey, and various laboratories 

 testing boiler and sanitary waters. I would emphasize the fact that they 

 do not contain much chlorine relatively. It is a notorious fact that over 

 a few parts per million of chlorine is considered a sign of sewage or other 

 contamination. 



Analysis (4) may pass as representative of pluvial and vadose water. ^ 

 The alkaline waters of arid regions are a group with which I am not 

 very familiar. So far as I have studied analyses of such waters, however, 

 the carbonates and sulphates of sodium and potassium dominate over the 

 chlorides, so that the ratio of sodium to chlorine is high. How high the 

 concentration may be in vadose arid land water I do not know, for it may 

 well be that analvsts have avoided them. 



CHLORINE CHARACTERISTIC OF SEA WATER 



It is not surprising that pluvial and downward working waters do not 

 contain much chlorine, for there are few minerals that contain chlorine : 

 Apatite, relatively rare and insoluble ; a little group of volcanic minerals ; 

 salt, and our tale is almost told. Unless these salt beds are in the neigh- 

 borhood, chlorine in the water in considerable quantity seems often to be 

 a sign of connate sea water. Furthermore, this fact is notable : If the 

 water is derived from sodium chloride we may be reasonably sure that 

 there will be at least enough sodium to combine with the chlorine, and in 

 general in superficial and river waters, and those that have derived their 

 mineral content by leaching, there is more than enough sodium for this. 

 But when we find this proportion of chlorine so great that there is more 

 than enougli to make sodium chloride, the inference becomes stronger that 

 there is an admixture either of buried sea water or possibly magmatic 

 waters" or leachings of a deposit like that of Stassfurt, which is, so far 

 as known, unique. 



As analyses which seem to show large proportions of buried sea waters 



* See also Roth and the TI. S. Geological Survey water supply papers passim_. 

 » Though the analyses collected by Lincoln. Economic Geology, 1907, p. 298, etcetera, 

 do not indicate any such preponderance of chlorine In such waters. 



