28 THE BOOK OF FORESTRY 



The value of our waterways in affording cheap trans- 

 portation to heavy freights has been overlooked for 

 some time on account of the greater popularity of the 

 railroads. Under present indications it appears that 

 canals and inland waterways of all kinds are coming 

 into their own. New York has spent over one hundred 

 million dollars on her barge canal and the people re- 

 cently voted in favor of an additional twenty-seven mil- 

 lion dollars to complete the work. There are altogether in 

 the United States 295 rivers, considered navigable and 

 the total length of their navigable waters amounts to 

 26,000 miles. Numerous State and local associations 

 are interested in their development and the use of these 

 inland waterways will doubtless be greatly increased 

 when terminals, etc., are constructed. The maximum 

 development of streams for navigation as well as for 

 power purposes depends directly upon even flow of the 

 run-off, which can best be maintained at the source by 

 keeping the watersheds perpetually under cover. 



Minerals. At the risk of being tiresome it can be 

 said regarding minerals as well as of lands and forests 

 that the United States has greater mineral wealth than 

 any country on the globe. While in the production of 

 gold our output is exceeded by South Africa, we excel in 

 variety, for there are only two or three metals of any 

 importance which are not found within our boundaries. 

 The most important metal which we lack is nickel. We 

 produce two-thirds the world's output of petroleum; 

 sixty per cent of its copper; forty per cent of its coal 

 and iron ; thirty per cent of its zinc. 



The former waste of some of these minerals has been 

 previously mentioned and their supply is by no means 

 endless. The supplies of high grade iron ore now in 

 sight will probably be exhausted by the year 1930, when 



