Since that time many ships fully equipped with arms have been sunk by torpedoes and have never seen the submarines which destroyed them. There is no way to attack submarines by gun fire unless they are seen, and commanders of submarines are becoming expert in concealing their presence. =Submarine Guns, Aerial Torpedoes, Searchlights.=--For an under-water gun to be effective, there must first be discovered some way to locate the target; this, of course, is almost impossible. Aerial torpedoes or depth bombs might be effective if the submarine were seen, but it is the business of the submarine commander to keep out of sight. Powerful searchlights have very little chance of picking up the periscope or conning tower of a submarine. I remember lying all one night in the _Argonaut_, during a storm, at the outer edge of the mine fields off Fortress Monroe, at the time the whole country was in dread of an invasion by Cervera's fleet during the Spanish-American War. We were in forbidden territory, having been delayed by the storm in getting into harbor before "Curfew" rang, so to speak. The powerful searchlights of Fortress Monroe were playing all night, but they did not detect our presence, as only our sighting hood was above water, and presented such a small object, and being painted white, it was not distinguished from the "white caps" on top of the sea caused by the storm. Searchlights under water are useless because of the particles of foreign matter held in suspension which reflect back the glare of the light. The _Argonaut_ was fitted with powerful searchlights and reflectors located in her extreme bow, with a pilot-house or lookout just above the three searchlight windows. The greatest distance we were ever able to see was during some night experiments in the Chesapeake Bay during a long dry spell, when the sediment had had an opportunity to settle, and that was only forty feet. The light would penetrate through the water several hundred feet and make a glow on the surface, but vision could not penetrate the water. For instance, it is said that after a storm a glass of Mississippi River water will show fully an inch of sediment. To see through three or four inches of that kind of water, therefore, one must see through an inch of mud. It is well known that no light has yet been found that will enable vision to penetrate through a heavy fog, due to the reflection of light upon the minute crystals of water held in suspension in the air. It appears hopeless, therefore, to expect vision to locate submarines by seeing through the opaque substance held in suspension in all water.