"No, but my people will batter those down," said Zingar in a low tone.
"Then we must prepare for defense," cried Dr. Henderson, "if they can break down the front door we must barricade every passageway and fight them back foot by foot. What is the substance of your ship's hull?"
"It is a very dense metal, unknown to you. None of your rays will penetrate it except the atom cannon."
"And we only have one old cannon, with hardly any of the power jackets—" groaned Dr. Henderson, desperately.
"We will save that for the last attack," said Zingar, calmly. "The disintegrators will hold the beasts back for a long time, but there are thousands of them. How many of the half-hour disintegrator charges do you have?"
"Not very many—The Earth Council was limited in its budget. Perhaps they would last one day of continuous firing."
IV
In two days the whole underground city was buzzing with activity. Mark Hemingway had improvised a laboratory and was isolating the various minerals of the corridor walls, seeking materials for ammunition. Major Mattson drilled all the able-bodied men and organized them under group officers. The crippled men and women were soon co-operating in a central factory unit, where hand forges, and smelting pits, were producing crude weapons of war. There were many women working, even at the heavier tasks. The enfeebled patients lay on their cots and rolled bandages, or did other light tasks.
Great stores of cooked food were being prepared against the day when every cook would be in the fighting lines. The able-bodied soldiers divided their time between drilling under Major Mattson, and erecting barriers as directed by old Jake, whose practical ingenuity used the abundant supply of cheap blasting powder to skillfully crumble corridor walls. Their one power crane heaped the rubble into thick barriers, each with a narrow defensible slit. Huge boulders were balanced, ready to fall into the opening when a flash match should be applied to a cloth fuse.