146 CHEMISTRY OF NATURAL WATERS. [IX. 



63. BORATES. The reddening of the yellow color of tur- 

 ineric-paper in presence of free hydrochloric acid affords, with 

 certain precautions, the ordinary means for detecting small por- 

 tions of boric acid. Most of the waters of the third and fourth 

 classes, and some of those of the second, have been tested in 

 this way, and have never failed when reduced to a small vol- 

 ume, and acidulated with hydrochloric acid, to give this re- 

 action ; which was, however, most marked with the waters of 

 the fourth class 



64. I have recently had an opportunity of examining from 

 California the waters of a borax-lake, which contains, beside 

 borate and carbonate of soda, a portion of chloride, and a little 

 silicate, traces only of phosphate, and no sulphate. It held 

 in solution very small quantities of earthy carbonate, and was 

 remarkable for the large proportion of potassium-salt which it 

 contains. The evaporated and fused saline residue was treated 

 by the ordinary methods for the determination of the chlorine, 

 carbonic acid, and silica ; while the bases were obtained in the 

 form of sulphates by the aid of sulphuric and hydrofluoric 

 acids, and afterwards separated as chlorides by the aid of chlo- 

 ride of platinum. From the data thus obtained the following 

 ingredients were found by calculation for 1,000 parts of the 

 water : 



Carbonate of soda . . . . . . 9.476 



Biborate of soda 4.395 



Chloride of sodium 1.702 



Carbonate of potash 1.818 



Silica 0.129 



17.520 



The potassium, as above determined, equals 11.46 per cent 

 of the bases weighed as chlorides; another trial gave 11.41. 

 Although for convenience we have represented the potassium 

 as carbonate, it will be seen that the amount of chlorine is 

 such that it might, for the greater part, have been represented 

 as chloride of potassium, with an equivalent portion additional 

 of carbonate of soda. 



