It sounds like magic, and indeed the witches were not in it when it comes to the achievements of modern science. But Reventlow has to confess that in practise the periscope is not so wonderful as it sounds in theory. The splashing of the salt water, unless the sea be perfectly calm, which it seldom is, soon dims and even effaces the image. It was long before the inventors could bring the periscope to reflect more than a small section of the horizon, but that difficulty seems to have been overcome.
It is possible, with map, clock and compass, to take reckonings and keep on a course even when deep down under water. Deeper than ninety feet the submarine seldom goes. It has found a new and unexpected enemy in the air-ship or aeroplane, for it is a well-known fact that from a height on a clear day, at least, you can see very far into the water. But what, one will ask, can the aeroplane do about it even if it sights a submarine far down beneath the surface? Projectiles would not be likely to do much damage. At the same time it can warn ships and can pursue and worry the submarine.
Search Lights
That the latter is not a perfect instrument goes without saying; indeed, when it darts about blindly it becomes a menace to its own ships. Its arrangements are so complicated, too, with all the letting in and out of water, the diving and coming up, the changing of motors and providing artificial air that things are very apt to go wrong. The service is extremely exhausting for the men and extremely dangerous.
Yet all the same the value of submarines is universally acknowledged and every great navy has them. They will probably prove useful in planting that new instrument of destruction, the floating mine, about which a few words must be said here: “It is to be presumed,” writes Reventlow, “that in the next naval war [how little he dreamed in November, 1913, that that war was so close at hand!] mines will play an important part not merely in coast defense but also in sea fights as a weapon with the same justification as artillery and torpedoes and that their use will materially influence the tactics to be employed.” As such a weapon of attack mines were first used in the Japanese-Russian War.
A Submarine About to Dive
A mine, as the reader probably knows, is a cask filled with high explosives and fastened by means of weights and anchors so that it floats some feet below the surface. Mines can be planted in fields, as it were, by torpedo-boats or submarine and then a hostile fleet can be lured or chased in among them. The North Sea, as we know, is at present thickly strewn with them and fatal results have already been chronicled. Air-ships and aeroplanes can help by finding the whereabouts of the hostile fleet and designating by wireless the spots where the mines should be planted.
Air-ships and aeroplanes will possibly find their chief use as coast-defenders. They need refuges to which they can retire, which limits their use on the high seas. But along the shore they can scout for hostile ships and also can detect submarines and mines. They can throw down explosives and, if they are near enough to the enemy’s harbors, can destroy docks and demoralize shipping. Already there is talk of specially armored decks and of great iron grills for protecting the openings of funnels.