254 JOSEPH M. SHEAHAN 



Among European producers the Iberian peninsula holds 

 the first place. Prior to 1882 its output exceeded the pro- 

 duction of the United States, and, in 1882, both countries 

 were on the same level, but within the following twenty years 

 the production of Spain and Portugal increased by only 

 about 25 per cent, while the production of the United States 

 is now more than seven times as large as it was twenty years 



ago. 



Mexico, which prior to 1894 was but a small factor m 

 the world's' production of copper, has since that year more 

 than trebled its output and gained third place among the 

 copper producing countries. 



Next after Mexico was Japan, which since 1890 has 

 doubled its output, and AustraHa, whose progress has been 

 still more rapid. Germany has shown no appreciable gains 

 since 1896, and has been outranked by Mexico and AustraUa. 



In the United States copper has been mined since the 

 early part of the eighteenth century and shipments of the 

 ore were made as early as 1731. The first deposits to be 

 worked were in Connecticut, New Jersey and Pennsylvania. 

 As an important industry, however, the history of copper dates 

 from 1844, when the Lake Superior region was opened. At 

 that time the country's output was small, but it grew steadily 

 and rapidly. In 1880, 27,000 tons were produced. Then with 

 the extension of railways through the west the rich deposits 

 in Montana and Arizona were opened to the markets of the 

 world and the United States rapidly left its rivals behind. 



In fact, the development of the western copper deposits 

 has given this country its present pre-eminent place among 

 the copper producing nations. 



The copper mines in the upper peninsula of Michigan 

 (the Lake Superior region) are unique. The ore is native 

 copper with some silver, but containing hardly any other 

 impurities. It is found as a cement binding together or 

 replacing the pebbles of a conglomerate, as a fiUing in an 

 amygdaloidal diabase, and as irregular masses in veins. 

 These veins have yielded immense masses of copper, but 

 because of their formation they cannot be worked at a profit 

 when copper prices are low. 



