12 



SCIENCE 



[N. S. Vol. XXXIII. No. 836 



Gold is mined for itself alone to a far 

 greater degree than is silver. Thus in this 

 country in 1908, almost 93 per cent, of the 

 gold was produced without regard to other 

 metals and only 7 per cent, was obtained 

 with copper and lead: whereas about 60 

 per cent, of the silver was produced in 

 association with the base metals. Gold in 

 later years has increased in amount of pro- 

 duction beyond all previous experience. 

 The steady and scientific digging and 

 washing of low-grade gravels are, in the long 

 run, more productive than the rich skim- 

 mings of the early California, Australia 

 and Klondike placers. The world's total 

 of 444 millions of dollars in 1908 was in 

 excess of any previous year. The Trans- 

 vaal furnished the most, nearly 146 mil- 

 lions. The United States followed with 96 

 millions; Australasia yielded 72.5; Russia 

 nearly 40; Mexico, 24.5; Rhodesia, 12.2 

 and British India, 10.4. All the rest were 

 under 10. The countries mentioned supply 

 about 90 per cent, of the total. 



In the United States 28 per cent, of the 

 gold comes from gravels and these are the 

 least permanent of the sources of the 

 metal. With their exhaustion the output 

 will decline. In the deep mines there are 

 signs of waning output in some districts. 

 In our own country new districts have come 

 to the front from time to time to give on 

 the whole a steady increase in output for 

 forty years past. So far as the future is 

 concerned, however, the ups and downs of 

 any one or of several countries make slight 

 difference in the world at large. Gold can 

 be readily shipped from point to point and 

 the place of its production is a compara- 

 tively small matter. 



Like silver and to an even greater de- 

 gree it resists chemical change, so that the 

 world's stock constantly augments. No 

 very important portion is permanently lost 

 in the arts. 



Gold and silver are so extensively em- 

 ployed in coinage that they have received 

 more attention at the hands of economists 

 than have any other metals. Gold in later 

 years, with its increasing production has led 

 to much philosophical speculation. The es- 

 tablishment of it as the monetary standard 

 and the elimination of silver from this 

 position have occasioned some of the most 

 heated political controversies in the his- 

 tory of our country. Into these a geologist 

 is not competent to enter. We all prob- 

 ably realize from old-time experience how 

 easy it is to become befogged. But the 

 geologist can say that for some years to 

 come the gold production will undoubtedly 

 be maintained. And that while the Klon- 

 dike and Alaska may wane, Siberia will in- 

 crease. 



We may now briefly summarize the main 

 facts affecting the six metals which have 

 been passed in review. It will then be pos- 

 sible to draw some general conclusions. 

 Of iron ore there is no lack, nor need any 

 one be apprehensive regarding the supply 

 of this metal, but before very many years 

 have passed the yield of the ore will have 

 decidedly declined. While the falling off 

 will be gradual, it will undoubtedly tend in 

 the long run toward forty per cent. This 

 change is in itself important because, un- 

 less otherwise neutralized it will raise the 

 cost of production. It makes necessary 

 the melting of more barren materials in the 

 furnace, so that the consumption of fuel 

 rises with respect to the amount of iron 

 produced. It means also the mining and 

 freighting of an additional burden which 

 yields no return. From whatever point of 

 view we regard it, other things being equal, 

 the cost of production rises. The great 

 reserves of lower grade ore than at present 

 mined are in the Lake Superior district. 

 They are siliceous ores, and will require in 

 smelting the admixture either of limestone 



