He shut off the power and hastened down to the motor room. There he found his men gathered about one of the machines. "What's wrong?" asked Tom quickly. "Just a little accident," replied the head machinist. "One of the boys dropped his monkey wrench and it smashed some spark plugs. That caused a short circuit and the left hand motor went out of business. We'll have her fixed in a jiffy." Tom looked relieved, and the machinist was as good as his word. In a few minutes the tank was moving forward again. It crossed out to the road, to the great astonishment of some farmers, and the fright of their horses, and then Tom once more swung her into the fields. "There's the old barn I spoke of," he remarked to Ned. "It's almost as bad a ruin as the factory was. But we'll have a go at it." "Going to smash it?" asked Ned. "I'm going right through it!" Tom cried. Chapter XVII Veiled Threats Like some prehistoric monster about to charge down upon another of its kind, Tank A, under the guidance of Tom Swift, reeled and bumped her way over the uneven fields toward the old barn. Within the monster of steel and iron were raucous noises: the clang and clatter of the powerful gasolene motors; the rattle of the wheels and gears; all making so much noise that, in the engine room proper, not a word could be heard. Every order had to be given by signs, and Tom sent his electric signals from the conning tower in the same way. When running at full speed, it was almost impossible, even in the tower, which was some distance removed from the engine room, to hear voices unless the words were shouted. "Why don't you go at it?" cried Ned to his "friend, who was peering through the observation slot in the tower." "I'm getting in good position," Tom answered. "Or rather, the worst position I can find. I want to give the tank a good try-out, and I'm going at the barn on the assumption that this is in enemy country and that I can't pick and choose my advance. "So I want to come up through that gully, and go at the barn from the long way. That will be the worst possible way I could do it, and if old Tank A stands the gaff I'll know she's a little bit nearer all right." "I think she's all right as she is!" asserted Ned in a yell, for just then Tom signaled for more speed, and the consequent increase in the rattling and banging noises made it correspondingly difficult for talk to be heard. The big machine now tipped into the little gully spoken of by Tom. This meant a dip downward, and then a climb out again and an attack on the barn going uphill and at an angle. But, as the young inventor had said, it would make a severe test and that was what he wanted to give his ponderous machine. Ned grasped one of the safety rings, as, with a reel to one side, almost as if it were going to capsize, the tank rumbled on. Tom cast a half-amused smile at his chum, and then threw over the guiding lever.