386 Introduction to the Study of Science 



The volume of freight handled annually on the Great Lakes, 

 for example, is enormous. Comparison with other waterways 

 is impossible, for there is no similar amount of shipping on in- 

 land waters in any other part of the world. The Suez Canal 

 is one of the busiest waterways ; but the volume of freight 

 handled by the Soo Canal is more than seven times that of 

 the Suez Canal. The tonnage is far more than 50,000,000 a 

 year, and a year there means a season of about twenty-five or 

 twenty-six weeks only. Through the river at Detroit more 

 than 70,000,000 tons of freight are transported each six months 

 of the shipping season. Approximately 80,000,000 tons of 

 freight are carried annually over the waters of the Great Lakes. 



This enormous amount of shipping is made necessary on the 

 western side by (1) the extensive and rich ore deposits of 

 ^Minnesota, Wisconsin, and Michigan ; (2) the far-reaching 

 grain-growing lands of the famous Red River Valley in Min- 

 nesota, the Dakotas, and Western Canada ; and (3) the timber 

 of the general western region sent mainly through the port at 

 Duluth. On the eastward side, the shipping draws from the 

 coal and manufacturing regions cargoes which are carried 

 across the lakes and distributed at many ports for railroad 

 transportation to inland points. At Duluth, for instance, the 

 grain elevators have a capacity of about 40,000,000 bushels, 

 and the ore docks hold more than 600,000 tons in the bins. 

 Other ports are equipped as their region of supply demands. 

 One giant corporation alone has a fleet of more than two hun- 

 dred vessels engaged in transporting ore to the amount of several 

 million tons a year. 



These few facts indicate the magnitude of the commerce of 

 the Great Lakes, and its importance to the many cities located 

 along the shores. Duluth, Superior, Two Harbors, Escanaba, 

 and Marquette are among the ports of supply, while Chicago, 

 Gary, Cleveland, Buffalo, and Toledo are well-known ports 

 of discharge. By this great waterway the products of the 

 East and Northwest are exchanged ; ores are brought to regions 



