The Use of Ships 
199 
ment. A channel 41 feet deep, 800 feet wide, and 50 miles in length 
had to be cut, largely in solid rock. Twelve pairs of locks had to be 
built so that the largest vessels could be lifted over a ridge from one 
v4 
F16. 141. The Panama Canal is about 50 miles long. The locks, which are at Gatun near the 
Atlantic and at Pedro Miguel and Miraflores near the Pacific, will accommodate the largest ships 
float. The canal took ten years to build. About the same tonnage now passes through it 
annually as goes throuch the Suez Canal. i 
ocean to the other. The ridge itself was cut down from 700 feet above 
sea level to 85 feet. A dam nearly a mile and a half long was con- 
structed to control the floods of the torrential Chagres River and to 
turn its valley into a great lake, now used as part of the canal. Both 
the dam and the lake are the greatest of their kind ever made by man. 
The engineering difficulties might have been overcome by the 
French when they attempted to build the canal, about thirty years be- 
fore the United States undertook it. But at that time it was difficult 
for native laborers to live at Panama. and almost impossible for white