SUBMARINE VESSELS 



some distance ahead of the boat, but this would defeat 

 the primary object of submarine attack, as such a 

 light would be seen by an enemy. 



In still water, when the boat is running within a dis- 

 tance of ten or fifteen feet of the surface, it is possible 

 to steer with great precision by the use of an optical 

 tube or "periscope." This periscope is a straight, 

 hollow tube, connected with the steering compartment 

 in the submarine, and protruding above the water. In 

 the upper end are a mirror and lenses so arranged 

 that the surrounding objects are reflected downward 

 through the tube, and show on a screen, or some other 

 device, so that the helmsman sees things of exactly the 

 same size that they would appear to the naked eye. 

 The periscope is also fitted with a telescope attachment 

 which magnifies objects like the binoculars used in 

 surface navigation. On some recent submarines there 

 are two periscopes, a movable one for use of the com- 

 manding ofl&cer, and one that looks straight ahead for 

 the helmsman's use. 



In still water the periscope works admirably, but it 

 is seriously interfered with even by small waves. It is 

 so small and inconspicuous, however, that it might 

 enable a submarine to creep within torpedo range even 

 in daylight, and launch the torpedo with accuracy, as 

 was proved in 1908 when a fleet of submarines actually 

 accomplished this feat in an experimental test. 



PRESENT STATUS OF SUBMARINE BOATS 



To most people, one of the most surprising things in 

 the Russo-Japanese war was the fact that submarine 



[ill] 



