8o6 THE POPULAR SCIENCE MONTHLY. 



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 caesium, is found not only of wide- 

 spread occurrence in our lithia micas, but the mineral spodumene, con- 

 taining 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 hundred- 

 weight 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 spe- 

 cies. Molybdenum, both as sulphide and in the oxidized form as 

 native molybdic acid and molybdate of lead, is found in many locali- 

 ties, 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 r utile 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 occur- 

 rences 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 terri- 

 tory has been explored with any thoroughness, and none of it exhaust- 

 ively. 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 Euroj^e 

 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 



