SOURCES AND PREPARATION OF MAGNESIA. 159 



Extraction of magnesia from sea- water.* " Magnesia is made 

 out of sea-water, which contains about 4 Ibs. magnesium chloride per 

 cubic yard of water, on a large scale at Aignes Morts, on the Mediter- 

 ranean coast of France. 



"The sea- water is pumped into a tank made of masonry, and at 

 the same time milk of lime is pumped in, in the proportion of 1.5 per 

 cent of lime for every 1 per cent of magnesia. From this first tank 

 the liquid flows into two other masonry tanks, when thorough mixing 

 is effected mechanically. It is then filtered into shallow excavations 

 about 1000 feet long and 16 feet wide, in the bottom of which is a bed 

 of clean beach-sand. When enough magnesia has been collected the 

 liquid supply is cut off and the precipitate is allowed to dry. If in 

 summer, it is dried in the sun, taking twenty to thirty days, but in winter 

 artificial drying is necessary." The dried magnesia is then calcined and 

 treated as explained in discussing the burning of magnesite (p. 154), 

 and the manufacture of magnesia bricks (pp. 160-161). 



References on magnesite, sources of magnesia, etc. 



. Hoffmann, G. C. Magnesite deposits in Quebec, Canada. Ann. Rep. Canadian 

 Geological Survey, vol. 13, Report R, pp. 14-19. 1903. 



Vlasto, S. J. The magnesite industry [in Europe]. Engineering and Mining 



Journal, March 10, 1900. 



atts, W. L. [Magnesite in Santa Clara County, California.] llth Ann. 

 Rep. California State Mineralogist, pp. 374-375. 1893. 



Weiss, N. Magnesite in Hungary. Iron Age, pp. 20-21. Jan. 15, 1903. 



Yale, C. G. [Magnesite deposits in California.] Mineral Resources U. S. 

 for 1903, pp. 1131-1135. 1904. 



Anon. Magnesite [in California]. 12th Ann. Rep. California State Mineralo- 

 gist, p. 328. 1894. 



Anon. Magnesite in Greece. U. S. Consular Report, No. 168, 1900. 



* Lock, C. G. W. Economic Mining, p. 331. 



