KEiJP. GEOLOGY AyD ECOyOMICS 369 



through Mr. Carnegie's spectacles. Much opposition arose at once, how- 

 ever, to Professor Tornebohm's data, because from them had been omitted 

 the red hematites of Alabama, which can be very accurately estimated 

 and which of themselves are thought by competent observers to have at 

 least a half billion tons for the future. Additional modifications must 

 also be introduced when we properly appreciate the downward tendency 

 of workable percentages. The lower the percentage of iron which we 

 require in the product of our mines, the greater the amount of ore which 

 at once becomes available. This is peculiarly true of iron, because of its 

 very wide, general distribution. 



In 1907, in anticipation of the International Geological Congress of 

 1910, which was to be held in Stockholm, the Swedish committee of 

 arrangements began the preparation of a series of estimates of iron re- 

 serves in all the countries of the globe. Geologists familiar with local 

 conditions were requested to prepare the figures each for his own country. 

 It fell to the speaker to start the collection of American estimates, and 

 much aid was afforded by several of the largest companies owning re- 

 serves. Shortly thereafter, however, the interest in the conservation of 

 natural resources sprang up, and Dr. C. W. Hayes, of the United States 

 Geological Survey, was empowered to use all the resources of this great 

 organization in assembling data on iron. In this way, figures as reliable 

 as can be expected are now available. We learn from them that we may 

 consider three and one half billion tons of fifty per cent, ore as assured in 

 the Lake Superior region. Of this great total of three billions, one hun- 

 dred millions are in the Mesabi range of Minnesota. At thirty millions 

 of tons per annum, the present output of Minnesota, we have a reserve 

 for a centur}'. 



On the other hand, if we drop to 40 per cent, or slightly below^ still, 

 however, remaining a few per cent, above the Alabama grade, the drill 

 holes show above depths no greater than those already reached in some 

 mines, two or tlii'ee hundred billions of tons of siliceous hematites, giving 

 amoimts practically inexhaustible. 



In the Alabama ore beds, we feel assured of five to six hundred million 

 tons of the grades now utilized, and there may well be twice that number. 

 The conservative estimate would afford enough to last at the present out- 

 put of that state longer than a century. In addition, there is much 

 reason for thinking that there may be two or three times as much. 



Speaking for the country as a whole, we may say that there is an as- 

 sured and demonstrated supply, at the present rate of output and the 

 present percentage of yield, for about a century. There is, furthermore, 

 a less accurately measured but still very probable addition, when we allow 



