The Great Salt Lake*A member of tbe geological survey says that Salt Lake will be of great value in tbe near future, not only on account of the common salt it will produce, bat also for tbe sodium sulphate it contain*. The latter Is separated in a floeculent precipitate by the cold weather of midwinter, and annually thrown upon the shore in enormous quantities. There are many other lakes in the far west whence an inexhaustible supply of commercial alkalies may be* obtained at small cost, Mono Lake, Cal., alone being estimated to hold over 78,000^000 tons of sodium carbonate.