Tom Swift and His Giant Robot by Victor Appleton II Read Free Book Online Page A

which was partially blocked from view. His hands now out of sight, Tom called: "Okay, pal— shake!"
    With a quizzical look Bud extended a hand—and then took a startled step backward. A white, tubular "stalk" snaked forth from the hidden top of the workbench, stretching like an elastic arm. The featureless, rounded column was about eight inches in diameter, somewhat broader at its base and tapering toward the fore-end approaching the youth’s outstretched hand. It curved through the air in an arch-shape, and as the nearer end slowly drew close to Bud he could see four stubby fingers and a thumb. This "hand" paused inches from Bud’s, as if waiting.
    "Well?" teased Tom.
    Bud hesitantly grasped the pseudo-hand and shook it. The whole stalk rippled up and down.
    "Feels—strange," he commented. "A little warm, and smooth—but not sticky. What is it, some kind of plastic?"
    "Yep," Tom replied. The eerie arm now slowly retracted the way it came until it was out of sight. "It’s another variation of Tomasite, compounded with some of the so-called ‘rare earth’ elements that are used in semiconductors. Our materials-science engineers have been working on it for some time now."
    Bud looked at his empty hand. Seeing it was perfectly clean, he scratched his head. "What do you do, pressurize it to make it expand like that?"
    Tom shook his head. "No, it’s an entirely different principle. As you know, a basic hydraulic system works because water is almost incompressible; if you push it down here, it bulges up there. That means you can use it to multiply force, just as a lever does."
    "Sure."
    "Now tell me this, flyboy. Why can’t a person pump sand, or other powders, in the same manner as you pump water?"
    Bud’s forehead crinkled. "I suppose it’s obvious… but I don’t know the answer!"
    Tom laughed. "Well, basically because of two factors. First, the grains don’t adhere to one another very well, whereas water molecules meld together, almost forming one big continuous molecule. The second reason is that the shape of the individual grains keeps them from fitting tightly together, so that a pile of sand, for example, is extremely porous."
    "If you spill a soda onto it, the liquid just runs right through."
    "Yes, and the result is that you can’t get enough suction going with sand, or most other powders, to overcome their internal friction and pump them."
    Bud smiled. "But Swift chemical magic has conquered that detail, right?"
    "You just saw the result," Tom confirmed. "It was basically a mass of plastic powder, made up of separate grains. But the new substance has unique electrical and mechanical characteristics. It conducts electricity with very low resistance—but only in one plane, along one direction, more or less. At right angles to the flow, it’s an almost perfect insulator. You could make a high-power cable of this stuff and hold it safely in your hand, with no insulation covering it."
    "Wild!"
    "Furthermore, a current causes it to structure itself into fibrils, like little threads, all along its length. The fibrils slide freely along one another, which makes the mass extremely elastic. But the individual fibrils are incompressible and hug closely, so it holds together—and you can pump it like water and use it for a hydraulic-like pressure system in the robot’s ‘muscles.’ See?"
    "Hey, of course!" Bud joked. "But what did you do to give it a shape and grow fingers?"
    "Just something I rigged up to test its capabilities," the other replied, gesturing toward the lab counter. "I have a sort of ‘sleeve’ back there with special sensors that modulate the current in the plastic, so that it imitates both the movement and general shape of my hand and arm."
    "That’s great, Tom," Bud said wonderingly. "What do you guys call the plastic powder?"
    Tom looked slightly embarrassed. "It has a big, long chemical name, but—don’t laugh—we’ve nicknamed it Herculesium!"
    "I wouldn’t laugh, pal," Bud