VARIATIONS IN COMPOSITION AND CONCENTRATION OF WATER OF 



SALTON SEA, 1912 AND 1913. 



By A. E. Vinson. 



The matter of the analysis of the annual sample of Salton Lake water was taken 

 over from Dr. Ross upon his departure from the Agricultural Experiment Station of 

 Arizona in 1911. The methods by which the results of 1912 and succeeding years were 

 obtained are identical with those used by Dr. Ross, and hence all results are strictly 

 comparable. (Table 16.) 



Table 16. — Composition of Salton Lake water, June 10, 191?. 



Total solids (dried at 110° C.) plus water of 



occlusion and hydration 846 . 55 



Water of ooclusion and hydration 23.9 



Sodium 270.71 



Potassium 3.81 



Calcium 17.28 



Magnesium 13.62 



Aluminium .100 



Iron 042 



Manganese none 



Zinc none 



Chlorine 395.44 



Sulphuric, SO ( 106.83 



Bicarbonio, HCOj (volumetrically) (12.15 



COj) 16.85 



Carbonic total, COa (gravimetrically) (12.09 



COj) 12.09 



Silicic SiO* 1.79 



Phosphoric, POj trace 



Nitric, NOi traoe 



Nitrous, NOi none 



Oxygen consumed .072 



The total soluble solids, including water by occlusion and hydration, for the period 

 of 373 days ending June 10, 1912, have increased 17.9 per cent; or about 17.5 per cent 

 for the even year ending June 3, 1912. This is somewhat less than the corresponding 

 increase of 19 per cent reported for last year. 



Calcium has increased 10.6 per cent, and magnesium 16.6 per cent. These lower 

 rates of increase, especially that of calcium, point to a considerable deposition of carbonate 

 of lime, especially about the edges of the lake, as already noted during the last two or three 

 years. Further evidence of the deposition of calcium carbonate is found in the relation 

 between the decrease in calcium and the decrease in the bicarbonate radicle. For the past 

 two years HC0 3 has been determined volumetrically. In 1911 HC0 3 = 17.14 per 100,000. 

 If HC0 3 had increased at the same rate as the total solids in 1912 it would have equaled 

 20.31 instead of 16.85, showing a falling off for 1912 of 3.46 HC0 3 per 100,000. In 1911 

 Ca = 15.62 per 100,000, and in 1912 at the normal rate of increase should have equaled 

 18.42 instead of 17.28, a falling off of 1.14 per 100,000. The HCO s corresponding to this 

 decrease of 1.14 Ca would equal 3.47 parts per 100,000, whereas 3.46 parts were found by 

 analysis. The additional HC0 3 required for the slight decrease in Mg would not exceed 

 the analytical error, although the ratio Mg : (HCOa)? is very high. 



An analysis, made by Mr. Catlin, of the incrustation formed on woody stems and stones 

 in the shallow waters and along the margins of the lake, gave the results shown in table 17. 



Per cent 



Water (at 110° C.) 2.02 



Silica (SiOs) 3.56 



Iron and aluminium oxides 1.68 



Calcium sulphate (CaSOt) 3.47 



Table 17. 



Per cent 



Calcium carbonate (CaCOj) 70.20 



Magnesium carbonate (MgCOi) 4.66 



Undetermined 14 -* 



The undetermined substances consist largely of the organic matter which it was 

 impossible to separate entirely from the deposit, and some alkali salts. 



Chlorine has increased 16.5 per cent and the sulphuric radicle 16.5 per cent over the 

 content of these constituents last year. 



47 



