A Complete Description of How to Make a Model Periscope with Working Drawings Together with a Simple Explanation of How a Real Periscope is Made And Works
ONE of the gravest faults the pilots of the first submarines had to contend with was that they were not able to see where their craft was going.
But like everything else that is needed for the welfare or warfare of the human race, inventors got busy and began to scheme and to experiment, with the big idea of making an instrument which would do for the submarine what the eye does for the brain, and that is to _look around_ with.
=How the Eye of the Submarine Got Its Name.=—Now, the eye of the submarine is called a _periscope_ and before we go any further let us find out how it came to get this peculiar name for then we shall know more of what we are talking about.
The early Greeks used two words that were very common to them, and you, too, will use them, before you get through with this chapter, just as easily as they did. One of these words is _peri_ which means _around_, and the other is _scopeō_ which means to _look_; so _peri_ plus _scopeō_ means to _around look_, or, as we barbarians say it, _look around_—which sounds better to us. And there you have the roots of the word _periscope_.
=The First Submarine Eye, or Periscope.=—As in the beginning of all things, good and evil, the first attempts to make an eye for the submarine, or a periscope, were very crude, and as usual they were nearly, if not quite worthless.
But the periscope was no exception to the first law of invention, and that is that each attempt, however much of a failure it may have been in itself, had the germ of a useful device in it; and from out of all these efforts finally came that wonderful optical instrument, the periscope.
We say _wonderful_ because with it an observer in the conning tower of a modern submarine, though it is all but submerged, can see everything that is taking place on the surface of the water around the whole horizon.
The earliest trials at making a periscope were by using a simple arrangement of mirrors of an “L” tube and each at an angle of 45 degrees. The best way to understand its construction is to make one for yourself.