226 EDWARD H. SANBORN 



whitewashed cavern, blasted and hewn from the soUd rock. 

 Thisjunique location is due to the fact that the spray from 

 the falls rendered it impossible to locate any power house 

 at the surface. The current is transmitted across the Cas- 

 cade Mountains through dense forests to the cities of Seattle 

 and Tacoma, where electric lights, railways, and motors are 

 operated; and, here again, it is to be noted that aluminum 

 is used for transmission circuits. 



The Saint Mary river, which flows from Lake Superior 

 into Lake Huron and separates the upper peninsula of Mich- 

 igan from Canada, has been utilized for power development 

 upon an extensive scale during the last few years. The condi- 

 tions here are somewhat different from the illustrations 

 previously described, as instead of a comparatively small 

 flow of water at great head, an enormous volume of water 

 with a comparatively small head is used. The difference in 

 the levels of the two lakes is about 20 feet, most of the fall 

 occurring in the rapids known as Saint Mary's falls, or Sault 

 Sainte Marie, at the outlet of Lake Superior. On the Cana- 

 dian side of the river a power canal has been in use for several 

 years, yielding about 20,000 horsepower, a large portion of 

 which is used direct from the turbines for driving wood pulp 

 grinders. The remainder is electrically transmitted to vari- 

 ous industries. 



On the American side of the river a much larger power 

 development is approaching completion. A canal about 

 2J miles in length, from 200 to 250 feet in width, and of an 

 average depth of about 20 feet, has been cut from Lake 

 Superior to a point on Saint Mary's river below the rapids. 

 A massive power house of steel, stone, and concrete, over 

 1,300 feet in length, will contain 320 horizontal turbines, 

 capable of developing about 50,000 horsepower. All of this 

 power will be transmitted by electricity to industries in the 

 vicinity on both sides of the river. 



A third canal of similar proportions is to be constructed 

 on the Canadian side of the river, paralleling the one now in 

 operation on that side. 



A unique feature of this great development is the pre- 

 caution taken to prevent possible lowering of the level of 



