The "periscope" is a device also of the nature of a camera obscura. In the case of the periscope a narrow metallic tube is thrust above the water and the shutter turned about, reflecting all the scene about on a white-covered table in the boat's cabin.
"I think I can beat you, Major," smiled Eph.
"I certainly hope you can," replied Major Woodruff. "That is what we want to see today. We shall watch closely, too, and see whether any plan can be devised for beating a submarine torpedo boat at its own game."
Lieutenant Kline was to remain on board the "Spitfire," both in order to watch the work and to give Eph any instructions that might be necessary in order to make the tests more conclusive.
"If you will come along with me, then, Mr. Benson," suggested Major Woodruff, "I will put you ashore on the neck. On the way over I will give you your instructions."
As the tug came alongside again Jack followed the major over the gang plank to the deck of the other craft.
"Good-bye, Captain Somers," called Jack, laughingly. "Give a fine account of yourself as an enemy of the United States!"
"Oh, you—" began Eph, flaring red, but wisely cutting his speech short.
On the way over to the strip of land known as the "neck" Major Woodruff managed to make his instructions wholly clear to young Benson.
"Now, you know what to watch for, and what observations, to report to me," finished the major of engineers, as the tug came to a stop. A small boat was lowered, and, in this, Captain Jack Benson was put on the desolate shore.