CHEMICAL WORK. 



121 



not sufficient to convert all the calcium carbonate to bicarbonate. Deep sea water affords 

 more or less free oxygen. (For Dittmar's results, see Rep. Chall. Exp., on ocean water.) 



The salinity or proportion of salts varies from dry winds, which tend to concentrate, 

 and from fresh-water streams, which dilute. The area of maximum salinity in the north 

 Atlantic is the Sargasso Sea, a region of calms between 25° and 35° N. and 30° and 20° W., 

 where the specific gravity is 1-0285 ; while that of minimum is in the region of equatorial 

 rains between 10° N. and the equator. In the south Pacific there is an area of maximum 

 specific gravity (1-02719) about the Society Islands. In general the salinity decreases 

 downward to 800 or 1000 fathoms, and then increases to the bottom. In the south At- 

 lantic the specific gravity at the bottom is 1-0257 to 1-0259, but in the north Atlantic it 

 is 1-02616 to 1-02632 at 2000 to 4000 fathoms (Buchanan). In the Baltic Sea, the salinity 

 is reduced one half or more by the waters from the rivers, and the maximum specific 

 gravity is only 1-0140. But in the Mediterranean, owing to evaporation and an average 

 rainfall of but 30 Laches, the specific gravity is 1-0280 to 1030 ; and hence the amovmt 

 of saline matters is about 3-9 per cent to 3-6 for the Atlantic. 



The following are analyses of two river waters, and of two mineral springs, from a 

 paper by Professor C. P. Chandler. The Croton River (supplying New York City) is from 

 a region of Archaean rocks ; the Mohawk, one of Lower Silurian shales, sandstones, and 

 limestones (underneath) ; and the two mineral springs arise from the Potsdam sandstone. 

 The amounts of mineral salts are of grains in a U. S. gallon (231 cubic inches = 57,750 

 grains) ; also mean of analyses of Arkansas Hot Springs, by R. N. Brackett (Ark. Geol. 

 Survey), temp. 124° and 146-5 F. 



Croton River, 

 N.Y. 



Potassium chloride — 



Sodium chloride 0-402 



Sodium bromide — 



Sodium iodide — 



Magnesium chloride — 



Potassium sulphate 0-179 



Sodium sulphate 0-260 



Calcium sulphate 0-158 



Magnesium sulphate — 



Calcium carbonate 1-648 



Magnesium carbonate. . . . 1-100 



Iron carbonate — 



Silica 0-621 



Organic, volatile 0-670 



Total 5-038 



Mohawk, 





Congress Springs, 



Lithia Well, 



Arkansas 



Utica, N.Y. 







Saratoga. 



Ballston. 



Hot Springs. 



0-12 







8-049 



33-276 





— 



0-17 







400-444 



750-030 





27 



— 







8-559 



3-643 





— 



— ■ 







0-138 



0-124 





— 



— Na 



. phosphal 



;e 0-016 



0-050 





■ — 



— 







0-889 



0-520 





0-21 



0-57 



Na. 



Carb 



. 10-775 



11-928 





0-45 



1-31 



Li. 



Carb. 



4-761 



7-750 





— 



— 



Ba. 



Carb 



. 0-928 



3-881 



Na^COj 



,0-04 



4-60 







143-399 



238-156 





7-15 



1-71 







121-757 



180-602 





1-13 



— 







0-340 



1-581 



FeSO, 



^0-05 



0-47 







0-840 



0-761 





2-58 



1-64 







trace 



trace 





— 



10-681 



700-895 1233-246^ 



11-88 



Pure water has very feeble solvent action on rocks except in the case of gypsum and 

 anhydrite, which yield 1 part to 400 to 500 of cold water. Quartz, feldspar, and other 

 siliceous minerals are essentially unaffected. Only 2 to 10 parts of calcite are taken up by 

 100,000 parts. Opal, which is silica in the soluble state (like that of Diatoms, Sponge- 

 spicules, Radiolarians), yields 12 to 15 parts to 100,000 parts of cold water, and much more 

 to warm water. 



1 The analysis afforded also 0-09 of alumina and iron oxide. 



2 This amount contains also 0-867 strontium bicarbonate and 0"077 alumina; and both the 

 Ballston and Saratoga waters afforded a trace of calcium fluoride and sodium biborate. The 

 carbonates in these waters are reckoned as bicarbonates. The Congress Spring afforded 392-289 

 cubic inches of carbonic acid to the gallon, and the Ballston, 426-114. 



