478 JOURNAL OF THS WASHINGTON ACADEMY OP SCIENCES VOL. 11, NO. 20 



surprising as it is said that in 1861 the lake dried up entirely. The 

 proportions of the principal salts appear to have changed somewhat 

 since 1863 as shown by the following percentages: 



The figures for 1863 give the approximate composition stated by 

 Whitney from Moore's analysis.^ The statement is incomplete and 

 the borax determination is open to question, but may be of the right 

 order. The figures for 1887 and 1921 are calculated from CI, total 

 CO2, and B2O3 and are therefore somewhat arbitrary inasmuch as 

 bicarbonates and metaborates are neglected. The latter are evaluated 

 as shown below. Since 1887 there appears to have been a slight gain 

 in borax and sodium chloride and a loss in sodium carbonate. In the 

 1921 sample the CI found was 11.6; SO4, 0.05; Ca, 0.06; Mg, 0.07; 

 CO2, 4.90; B2O3, 1.62; K, 0.56 grams per liter. The titration al- 

 kalinity to methyl orange was 0.214 normal. 



The alkaline character of the water may be expressed through the 

 hydrogen ion concentration as ^^ = 9.75. This measurement was 

 made electrometrically, as described elsewhere.* The water is actually 

 somewhat more alkaline than the Searles lake brine (for which p^ = 

 9.48) although it is far less concentrated in total salts. This peculiarity 

 is caused by the large salt effect in Searles brine. 



In order to represent the dissolved alkaline matter in the form of 

 the customary buffer salts, as has been done for Searles brine, ^ an 

 artificial water, containing 18.5 g. sodium chloride, 0.5 g. magnesium 

 chloride, 1.0 g. potassium chloride, and 0.03 g. calcium sulfate per 

 liter was made up as a medium to which buffer salts could be added 

 and the resulting ^^ values determined. A set of p^^ determinations 

 was then made with various proportions of sodium carbonate and 

 bicarbonate, keeping the total CO2 equal to that found in the lake 

 water. Another similar set was made with mixtures of borax and 

 sodium metaborate keeping the total B2O3 the same as found in the 

 lake water. The results are given in table 1 and plotted in figure 1 . 



3 Calif. GeoLSurv.l: 98. 



* Journ. Amer. Chem. Soc. 42: 2160. 1920. For general directions, Clark, The 



determination of hydrogen ions. 



^ Joum. Eng. Chem. 13: 691. 1921. 



