THE CONQUEST OF TIME AND SPACE 



been established in submarine navigation; and the 

 simplicity of this method naturally helps its popularity. 

 If there were no shifting of weight in a submarine, or 

 no wave disturbance, it would not be difficult to set 

 the rudders at such an angle that the boat would travel 

 for long distances at an approximately uniform sub- 

 mergence, the depth of submergence being indicated 

 by gauges acted upon by the water pressure on the 

 surface of the boat. And in actual practice it is possi- 

 ble to do this at the present time, part of the problem 

 having been solved by automatic and other devices. 



It should be remembered that many things enter 

 into the disturbance of the submarine's equilibrium. 

 The movement of a member of the crew from one 

 point to another shifts the ballast; a certain amount 

 of leakage of water cannot be avoided, and the sudden 

 discharge of a torpedo weighing several hundred pounds 

 from her bow tends to bring the boat quickly to the 

 surface if this lost weight is not compensated for quickly. 

 By various ingenious devices all these difficulties have 

 been practically overcome, most of them automatically. 



But the great unsolved problem of submarine navi- 

 gation — practically the only one that now opposes a 

 question mark to its great utility in warfare — is that of 

 steering with certainty of direction when submerged. 

 Once the submarine is under water it is in utter dark- 

 ness as far as seeing to steer is concerned; and what 

 adds to the difficulty is the fact that the compass can- 

 not be relied upon, because of the surrounding elec- 

 trical apparatus. It would be possible, perhaps, to 

 construct a powerful electric lamp to throw a light 



[no] 



