"Well, aren't we going to take any guard ships along?" inquired Alfred.
"Oh yes; six of the machines will be armed, but we must use every ounce we can carry on the Seraph. Before starting we must go over the route, as similar instructions will have to be issued to all of the flyers," remarked the lieutenant.
"Do you know where we are to go?" asked Ralph.
"The objective point is Mannheim on the Rhine. The river is eighty miles due east, and Mannheim is about fifty miles farther down the river. That city is on the eastern bank of the river, and Ludwigshafen is a small town, on the opposite shore where the great laboratory of Badische Analin and Soda Fabrik is located," remarked the lieutenant.
"So we are going to destroy a soda factory?" said Ralph with a grin.
"Not exactly," replied the lieutenant, amused at the intimation. "The principal thing turned out at the plant before the war was nitrate, a chemical most essential in the manufacture of explosives, and the importance of the place may be understood when I tell you that fully two-thirds of this product used by the Germans comes from that place."
"When will the start be made?" asked Ralph excitedly.
"Tomorrow," was the reply.
"Then I want to see the map," said Ralph.
"By all means," answered the lieutenant. "Now, you will notice that here is a canal shown on the map which runs due east. That is the Rhine-Marne, which parallels this river, the Zorn. The Zorn flows into the Rhine at Strassburg. You know, of course, that rivers, or canals, are the best guides for our purposes, so we must get these firmly fixed in our minds."