206 NEW YORK STATE MUSEUM 



Before the discovery of radium in 1898, but little attention was 

 given to uranium ores in America, though some little pitchblende 

 was shipped from the Central City, Colorado, region for use in 

 making uranium compounds. Shortly after the discovery of radium, 

 however, mining was begun on the carnotite of southwestern Col- 

 orado, and from 1900 to 19 10 several companies were formed to 

 work these ores both in Colorado and Utah. The pitchblende of 

 Central City also began to attract renewed attention. For a few 

 years active work was done in prospecting for it, but the quantities 

 have so far proved to be small. A few tons probably represent the 

 total amount derived from these mines since the search began. In 

 .the meantime, however, the production of carnotite increased rapidly 

 until 191 5, when it greatly decreased on account of the curtailment 

 of shipments to Europe. In the latter part of 19 16, however, the 

 production increased again, on account of the increased consump- 

 tion of ore in this country, and today the production is very active, 

 largely on account of the increased use of radium not only in medicine 

 but especially in luminous paints. 



The amount of radium and uranium ores produced in the United 

 States, or in fact anywhere, during a given period, is difficult to 

 determine on account of the different bases on which reports are 

 made. Some reports give the weight of crude ore produced with- 

 out giving the per cent of uranium; others give the weight of uranium 

 oxide contained and not of crude ore; others give the amount of 

 radium element or uranium element produced without giving the 

 amount of ore used in the production. For these reasons only 

 more or less vague and disconnected estimates of production are 

 available, but it may be said that the tonnage is small compared 

 with that of ores of commoner metals, a few thousand tons being 

 a large amount of carnotite, and simply a few tons or pounds being 

 a large amount of pitchblende. Though the mining of radium and 

 uranium ores in the United States began about 1900 or shortly before, 

 no very large quantities were produced until 191 2, when about 1100 

 tons were mined, consisting chiefly of Colorado carnotite. The pro- 

 duction has gradually increased until now it is several thousand tons 

 yearly, practically all of which is carnotite from Colorado and Utah. 



RADIUM AND URANIUM RESOURCES OF EUROPE' 



Joachimsthal, Austria. The most important radium and uranium 

 ore at present in Europe, is the uraninite or pitchblende found in 

 the mines of Joachimsthal in Bohemia, Austria. It occurs as a 



