The Boy Volunteers with the Submarine Fleet Part 19

"Do you wish to remain?" he asked.

"The chances of that fellow seem to be pretty slim. I would like to see the finish of the game; but I suppose we ought to get into port as soon as possible," answered the captain.

"Then I will give the order to proceed," replied the lieutenant.

The captain nodded, and the boys started for the door.

"One moment!" said the captain. "We may still be able to see an interesting sight."

The boys rushed out of the door. Glancing up at the deck of the chaser they could see the marines aboard rus.h.i.+ng to the side of the vessel. As they looked at the buoys it was noticed that they were silent.

_L'Orient_ was slowly backing away from the obvious location of the submerged vessel.

"They are about to throw a sh.e.l.l," observed the captain.

The remark had hardly left his mouth when an explosion was heard and the sh.e.l.l could be observed moving upward at a very high angle, and descending into the water with a vicious plunge.

No sooner had it struck the sea than it seemed to raise the surface of the water like the foaming ma.s.s in a boiling pot. The explosion was dull, vibrant, ominous.

"They are shooting another one," shouted Alfred, although he tried to suppress his voice.

"Boom!" came the sound, as he uttered the words.

The second shot struck the water not fifty feet distant from the first one.

"Do you think they will fire another?" asked Alfred.

"Probably not," answered the captain.

"What is that little boat going over there for?" asked Ralph, as one of the torpedo boats boldly advanced over the spot where the two sh.e.l.ls had entered the water.

The captain nodded his head for a few moments before speaking.

"The shots were successful."

"I can see that now," said Ralph. "Look at the oil coming up and covering the sea."

It was, indeed, a sad sight to witness, knowing that the shots meant the death of thirty or more human beings.

"Well, I am awfully sorry for them, even if they had no sympathy for us, and didn't wait to see whether or not we were put into safety before they sent our s.h.i.+p down," said Alfred reflectively, as he turned and entered the conning tower.

The scene had its fascination for Ralph, although he felt the horror of it all as he stood leaning over the railing, gazing at the patrol boats which were sailing back and forth in and around the spot where the petroleum was fast covering the surface of the water in all directions.

"You can understand now, can't you, why flying machines are such good spotters for submarines?" remarked the captain.

"Do you mean the oil that comes on top of the water?" asked Ralph.

"Yes," was the reply.

"But does oil arise at all times when a submarine is submerged?" asked Ralph.

"More or less oil is constantly detaching itself from the body of the hull, at the discharge ports, and it can't be helped because all of the gas discharge ports are under water at all times, whether the vessel is running on or under the water, hence, as it moves along it will leave a trail of oil which can be easily detected by a machine in flight above the surface of the water," said the captain.

"But doesn't a machine, when it is under the water, leave a ripple that is easily seen by a flying machine?" asked Ralph.

"Yes; I was going to refer to that," replied the captain. "An aviator has a great advantage over an observer on a vessel, for the reason that the slightest movement of the surface of the sea, even though there may be p.r.o.nounced waves, can be noted. If the submarine is moving along near the surface, the ripple is very p.r.o.nounced, and the streak of oil which follows is very narrow. Should the submarine stop, the oil it discharges acc.u.mulates on top of the water at one place, and begins to spread out over the surface of the water and this makes it a mark for the watchful eye of the airmen of the sea patrols," answered the captain.

"I heard one of the officers at the aviation camp say that a submarine could be seen easily through fifty feet of water by an airman," remarked Alfred. "Do you think that is so?" he asked.

"I know it is possible," replied the captain.

"But why is it that when you are on a s.h.i.+p it is impossible to see through the water that depth?"

"For this reason," answered the captain: "if you are on a s.h.i.+p, and you are looking even from the topmast of the vessel, the line of vision from the eye strikes the surface of the water at an angle. The result is that the surface of the water acts as a reflector, exactly the same as when the line of sight strikes a pane of gla.s.s."

"Do you mean that the sight is reflected just as it is when you are outside of a house and try to look into the window at an angle?" asked Ralph.

"Exactly; that is one explanation. The other is this: sea water is clear and transparent. By looking down directly on the water, a dark object, unless too far below the surface, will be noted for the reason that it makes a change in the coloring from the area surrounding it, and a cigar-shaped object at fifty feet below, whether it should be black or white, would quickly be detected," explained the captain.

"I remember that Lieutenant Winston, who has flown across the channel many times, told me that he could tell when he was nearing land, in a fog, by sailing close to the water, even though the land couldn't be seen. Do you know how he was able to do that?" asked Ralph.

"That is one of the simplest problems," replied the captain. "The shallower the water the lighter the appearance to an observer in an airs.h.i.+p. As the water grows deeper the color seems to grow greener and bluer, the bluest being at the greatest depth."

The chaser was now under way, and described a circle to the right. The captain, after saluting the officer on the bridge of _l'Orient_, gave the signal "Forward," and slowly the submarine sheered about and followed.

The second line of buoys appeared a quarter of a mile to the east of the one they had just left. In a half-hour the two vessels pa.s.sed through the gateway and turned to the north.

"We can't be very far from England," remarked Alfred.

"I judge we are fifteen miles from Dover," replied the captain.

"Do you intend to go to Dover?" asked Ralph.

"No; there are no stations there that can receive crafts of this kind. I do not know to what point they may take us; possibly to the mouth of the Thames, and from there to some point where the vessel will be interned,"

answered the captain.

"How deep is the channel here?" asked Ralph.

"Probably not to exceed 120 feet," was the reply.

"Not more than that in the middle of the Channel,--half way between England and France?" asked Alfred in surprise.

"No; the Channel is very shallow," answered the captain.

"No wonder then," said Alfred, "that the submarines are having such a hard time getting through, even though they don't have the nets!"

Having pa.s.sed the cordon of nets the chaser turned and slowly steamed past the submarine. The lieutenant stepped to the side of the bridge and said:

"I suppose, Captain, you can now make the pier-head at Ramsgate, where you will get a s.h.i.+p to convoy you to the harbor. Good luck to you!

Adieu!"