Free Cities in Flight by James Blish Page B

dared to seek out and muffle: "This looks like a real line, Bliss. On Subject G." (Something on gravity, chief.)
    "Keep it to the point." (A reminder: Keep it too technical to interest a casual eavesdropper-if you have to talk about it here, with all these bugs to pick it up.)
    "Sure. It's a thing called the Blackett equation. Deals with a possible relationship between electron-spin and magnetic moment. I understand Dirac did some work on that, too. There's a G in the equation, and with one simple algebraic manipulation you can isolate the G on one side of the equals-sign, and all the other elements on the other." (Not a crackpot notion this time. Real scientists have been interested in it. There's math to go with it.)
    "Status?" (Why was it never followed, then?)
    "The original equation is about status seven, but there's no way anybody knows that it could be subjected to an operational test. The manipulated equation is called the Locke Derivation, and our boys say that a little dimensional analysis will show that it's wrong; but they're not entirely sure. However, it is subject to an operational test if we want to pay for it, where the original Blackest formula isn't." (Nobody's sure what it means yet. It may mean nothing. It would cost a hell of a lot to find out.)
    "Do we have the facilities?" (Just how much?)
    "Only the beginnings." (About four billion dollars, Bliss.)
    "Conservatively?" (Why so much?)
    "Yes. Field strength again."
    (That was shorthand for the only problem that mattered, in the long run, if you wanted to work with gravity. Whether you thought of it, like Newton, as a force, or like Faraday as a field, or like Einstein as a condition in space, gravity was incredibly weak. It was so weak that, although theoretically it was a property of every bit of matter in the universe no matter how small, it could not be worked with in the laboratory. Two magnetized needles will rush toward each other over a distance as great as an inch; so will two balls of pith as small as peas if they bear opposite electrical charges. Two ceramic magnets no bigger than doughnuts can be so strongly charged that it is impossible to push them together by hand when their like poles are opposed, and impossible for a strong man to hold them apart when their unlike poles approach each other. Two spheres of metal of any size, if they bear opposite electrical charges, will mate in a fat spark across the insulating air, if there is no other way that they can neutralize each other.
    (But gravity-theoretically one in kind with electricity: and magnetism-cannot be charged on to any object. It produces no sparks. There is no such thing as an insulation against it-a di-gravitic. It remains beyond detection as a force between bodies as small as peas or doughnuts. Two objects as huge as skyscrapers and as massive as lead will take centuries to crawl over a foot of distance, if nothing but their mutual gravitational attraction is drawing them together; even love is faster than that. Even a ball of rock eight thousand miles in diameter has a gravitational field too weak to prevent one single man from pole-vaulting away from it to more than four times his own height, driven by no opposing force but that of his spasming muscles.)
    "Well, give me a report when you can. If necessary, we can expand." (Is it worth it?)
    "I'll give you the report this week." (Yes!)
    And that was how the Bridge had been born, though nobody had known it then, not even Wagoner. The senators who had investigated the Bridge still didn't know it. MacHinery's staff at the FBI evidently had been unable to penetrate the jargon on their recording of that conversation far enough to connect the conversation with the bridge otherwise MacHinery would have given the transcript to the investigators. MacHinery did not exactly love Wagoner; he had been unable thus far to find any handle by which he might grasp and use the Alaskan senator.
    All well and good.
    And yet the investigators had come