"There's something else I'd like to know," said Ben. "And that's whether they had time to warn the rest of the Lassans what they were up against. If they did, we stand a chance. The way I have these guys figured is that they're good, but they have a yellow streak, or maybe they're just lazy, and they don't like to fight unless they're sure of winning. If I'm right we'll have time to get _Monitor II_ into commission and before they come out again, we'll be ready for them. If I'm wrong we might as well find a nice hole somewhere and pull it in after us." "Yes, and on the other hand, if they did have time to warn them, they'll sit down and dope out some new trick. Though I have a hunch they won't find an answer to that gravity-beam so easily. There isn't any that I know of." "Well, anyway," said Murray Lee, "nothing to do till tomorrow. What are you two rummies up to now?" "Run up and push them along on _Monitor II_ if we can," replied Ben. "I think I'll round up the rest of the mechanical Americans and put you all to work on it. We can work day and night and get it done a lot quicker." "Me," said Sherman, "I'm going to figure out some way to install radio on that new bus or bust a button. That's one thing we ought not to do without. If we'd known the position of that green lemon before we saw it, we could have dived out of the clouds on it and made it the first shot before we got all racked up with that yellow ray." CHAPTER XXI Reinforcements The little group separated, going about their several tasks. From whatever cause, Ben proved to be right about the Lassan green spheres. After that one brief incursion, in which they had wrecked the greater part of Newark and most of the artillery the Australians had established to bear on the door of the Lassan city, they seemed to have returned to their underground home, realizing that the earth-men still had weapons the equal of anything the creatures of Rigel could produce. For a whole week there was no sign of them. Meanwhile, the federated army dug itself in and prepared for the attack that was now believed certain. The success of the first _Monitor_ had been great enough, it was decided to warrant the construction of more than one of the second edition. General Grierson wished to turn the whole resource of the Allied armies to building an enormous number, but under Ben's persuasion he consented to concentrate on only five. For, as Ben pointed out to the general, the training of flesh and blood men for these craft would be labor lost.