644 Jenkins — Spotted Lakes of Epsomite. 



must have perished, and their decaying carbonaceous 

 remains were added to the general clayey mass already 

 accumulated. 



The cones appear to have been formed by the gradual 

 penetration of rising solutions from the lower layer and 

 by its recrystallization in this newly acquired position. 

 Each crystallization of the material helped to open up, 

 by its expansion on forming crystals, a larger space, until 

 the surface was reached. The appearance on the surface 

 is that of circular bodies, or of spots when viewed from a 

 distance. 



The expanding force of the crystallization of magne- 

 sium sulphate is well illustrated at the salts plant. The 

 operators state that at times during winter, after a 

 sudden drop of temperature, a saturated solution, pass- 

 ing from tank to tank in a three-inch pipe, has crystallized 

 with such force of expansion as to split the pipe from end 

 to end. It was also found that the crystallizing salts 

 could not be kept in wooden tanks, for the percolating 

 solutions would work into the cracks and, upon crystal- 

 lizing, would open up the joints between the boards, caus- 

 ing them to leak so that they had to be lined with metal. 



The principal uses of epsomite are in medicine, in the 

 tanning industry, and in the manufacture of various com- 

 pounds of magnesium. It is artificially prepared else- 

 where from dolomite and magnesite, and before the 

 European war it was shipped to this country as a by- 

 product of the potash industry in Germany. 



State College of Washington, 

 Pullman, Washington. 



