278 REPOBT OF NATIONAL MUSEUM, 1899. 



rocks in Lancaster County, Pennsylvania, by McKim, Sines and Com- 

 pany, of Baltimore, by whom it was used for the manufacture of 

 Epsom salts (sulphate of magnesia). 



Although it is said 1 that these gentlemen made a pure salt at less 

 price than it could be imported, and thereby excluded the foreign 

 material almost exclusively, the mines are now wholly abandoned. 

 Isaac Tyson & Co., of this same city, also operated mines in Lan- 

 caster County. 



Early in the fall of 1886 a small force of men was set to work on the deposits of 

 magnesite discovered on Cedar mountain, Alameda county, California. Since that 

 time several carloads of the mineral have been gotten out and shipped by rail to 

 New York, these deposits being only a few miles from the line of the Central Pacific 

 Railroad. The mineral occurs here in a decomposed serpentine rock and in a yellow 

 clay in which are embedded large bowlders. It lies in pockets and small veins, the 

 latter running in every direction. The richest spots are found under the bowlders, 

 where the mineral is quite pure. A machine is used to sift out the small stones from 

 the powdered magnesite, a good deal of which is met with. A number of veins of 

 this mineral has been exposed by the occurrence of landslides on the side of the 

 mountain where they are situated; only a few of them, however, contain good 

 mineral, nor is there any certainty as to how long these will last. The claims are 

 being opened by tunnels, of which two have been started. The process of gathering 

 this mineral is slow, as every piece has to be cleaned by hand and the whole has to 

 be carefully assorted according to purity. Having been divided into three classes, it 

 is put up in sacks weighing from 80 to 100 pounds each. This sacking is preliminary 

 not only to shipping but to getting it down from the mountains, which can be done 

 only on the backs of animals. While carbonate of magnesia occurs at a great many 

 places in California and elsewhere on the Pacific coast, the above is the only deposit 

 of this mineral that is being worked. An artificial article of this kind is obtained as 

 a by-product in the manufacture of salt by the Union Pacific Salt Company of 

 California. 2 



Th. Schlossing has proposed 3 to utilize magnesian hydrate obtained 

 by precipitation from sea water by lime, for the preparation of fire 

 brick, the hydrate being first dehydrated by calcination at a white 

 heat, after which it is made up into brick form. 



According to the Industrial World* magnesite as a substitute for 

 barite in the manufacture of paint is likely to prove of importance. 

 The color, weight, and opacity of powder add to its value for this 

 purpose. In Europe it is stated the material is used as an adulterant 

 for the cheaper grades of soap. 



Prices. During 1892 the material, 96 to 98 per cent pure, was quoted 

 as worth $9 to $15 a ton in New York City. Material containing as 

 high as 15 to 30 per cent silica and 8 to 10 per cent of iron is said to 

 be practically worthless. In 1899 crude California magnesite was quoted 

 as worth $3 a ton at the mines. 



1 Report C. C. C. Second Geological Survey of Pennsylvania, p. 178. 



2 Mineral Resources of the United States, 1886, p. 696. 

 3 Comptes Rendus, 1885, p. 137. 



industrial World, XXXVI, No. 20, 1891. 



