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Page:Popular Science Monthly Volume 21.djvu/824

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mineral that in America has a wide range of localities, and recently this species has been found in crystals of two, three, and, in one instance, of eight pounds in weight. Again, three new earth-metals—mosandrum, phillipium, and decipium—have been described as occurring with the cerium earths and yttria in the North Carolina samarskite. The rare alkali metal lithium, sometimes associated with the still rarer metals rubidium and cæsium, is found not only of widespread occurrence in our lithia micas, but the mineral spodumene, containing from five to eight per cent of lithia, occurs by the ton in at least one locality, and must be looked upon as one of the common American minerals, being found in the granite veins in Maine, New Hampshire, Massachusetts, and Connecticut, and as far south as North Carolina and Georgia. Lithia also is one of the constituents of the phosphate triphilite, and there are several localities known where this mineral occurs abundantly. Again, we have the frequent occurrence of some of the rare metals which form metallic acids: Columbium, the first metal, new to science, discovered in America, associated with its twin metal tantalum, is found in columbite in our granite veins from Maine to Georgia, a range of more than a thousand miles, in a score or more of places, and sometimes is obtained by the hundredweight at a single locality. The American variety of samarskite, another rare columbate, has also been found in masses of fifty pounds or more in weight, and these acids occur in still other American species. Molybdenum, both as sulphide and in the oxidized form as native molybdic acid and molybdate of lead, is found in many localities, and occasionally in large quantity. Quite recently vanadium compounds have been discovered in several places, and tungstates have also been observed over a wide range of country. Titanium has been found in enormous quantities in extensive deposits of titanic iron as well as in the form of rutile and in sphene. The rare metal tellurium occurs native in Colorado in one locality, where single masses of twenty-five pounds in weight have been taken out, and several new tellurium compounds have been found in our Western mines.

It is, perhaps, unnecessary to enumerate more fully the many occurrences of other rare elements in American minerals. Enough has already been said to show that important developments have been made in the discovery and investigation of the minerals found in our American rocks during the past eighty years. Nevertheless, it is but a commencement in the work. Only a very small portion of our territory has been explored with any thoroughness, and none of it exhaustively. The enormous production of the precious metals and the extensive deposits of ores of the more common metals which have been opened up during the past twenty or thirty years have placed us in the front rank as metal-producers, but we are still far behind Europe in the variety of minerals obtained from our mines. This may be due, in some instances, to the character of the veins or ore-deposits, there