156 Book of Engineering 



Every stagnant piece of water was either 

 abolished or so treated that the deadly 

 mosquito found no safe hiding place for 

 her eggs. Malaria and yellow fever had been 

 tracked down to this hateful insect, and 

 though perhaps no one would yet consider 

 the canal zone a health resort it is fortu- 

 nately true that white men are free far 

 more there from the disadvantages of a 

 tropical climate than in many other parts 

 of the New World. 



Gatun Lake is rather a favourite stretch 

 of water with shipowners for they find here 

 some recompense for the necessarily heavy 

 tolls which they must pay. The water of 

 Gatun Lake has this curious property that 

 it dissolves very quickly the marine growths 

 upon the hull of a vessel which so tend to 

 slow her speed. The period between dry 

 docking a ship that uses regularly the 

 Panama Canal may be extended consider- 

 ably through this strange property of Gatun 

 water. 



In length the lake is about 23 miles, 

 and from it the ship enters the celebrated 



