2J2 The West American Scientist. 



ties, which property fits it for certain purposes and uses in the 

 arts. Pure salt does not deliquesce except in a very moist at- 

 mosphere. 



Salt obtained artificially contains various impurities which im- 

 pair its value. These impurities are generally magnesia, gypsum, 

 bromine and iodine, with much organic matter, while rock salt is 

 fi'ee fi'om them. This has led to the theory that seawater takes 

 its salt from beds of rock salt, instead of rock salt being deposited 

 from the ocean This theory is strengthened by the fact that 

 rock salt is sometimes absolutely anhydrous. 



While inferior salt may be extracted from brines found in nearly 

 all countries, rock salt is rather rare. It occurs in very large de- 

 posits in England, Poland, Hungary and Germany. Jn the high 

 mountains of Chili it is met with at an elevation of 9000 feet above 

 the sea level. In Spain. 16 leagues from Barcelona, there is a 

 mountain of salt three miles in circumference and 500 feet high. 

 It is quite pure. No gypsum is found with it. This mineral has 

 been found also in considerable quantities in New South Wales. 



It has long been known that rock salt existed in very large 

 quantities in Nevada and Arizona. On Holt's map of California 

 and Nevada, published in 1876, a deposit in Lincoln County, 

 Nevada, is described as being five miles long and 600 feet high. 

 This locality lies 53 miles, by the scale of the map, a little west 

 of north from Callville, on the great bend of the Colorado river. 

 Some years ago I examined specimens and found them to be very 

 pure. 



In Cleveland's "Mineralogy," published in 1816, I find a state- 

 ment that, "rock salt is found in California in very solid masses." 

 The writer probably referred to the peninsula of Lower Cali- 

 fornia. 



In the sink of the Colorado desert in San Diego County, de- 

 posits of salt have been discovered, and are rather extensively 

 worked, but this salt is probably the result of the evaporation of 

 the waters of an ancient inland sea, cut off from the great ocean 

 by the delta of the Colorado river, or by an upheaval of land, 

 gradual or otherwise. The water, under the influence of the sun 

 and the dry climate of the locality, became less until a resultmg 

 small lake of concentrated sea-water finally diied and left the de- 

 posit of salt. This is a good theory until a more thorough study 

 of the deposit is made. It is now covered by silt and debris 

 washed down over it during many winters of rain-storm and cloud- 

 burst 



The associate minerals often found with rock salt have also 

 great value. Chloride of potassium in very large quantities is ex- 

 tracted from beds overlying the salt deposits at Stassfurt, in 

 •Saxony. Some idea of the quantity may be inferred, when the 

 statement is made, that, in 1863-64, 400 tons of carnallite were 

 raised. The yield increased annually until 1875, when the pro- 



