"Correct," Dr. O'Connor said. "And another factor is the time, _t_. What we are measuring here is the span of attention of the individual--the ability of the subject's mind to concentrate on a given thing for a span of time. Many people, for example, cannot keep their attention focused on a single thought for more than a few milliseconds, it seems. They are ... ah ... 'scatter-brained,' as the saying is." His expression left no doubt that he included Malone in that group. Malone tried not to look nervous. Then Dr. O'Connor scowled. "There is another factor which we feel should be in the equation," he said, "but we have not yet found a precise way to express it mathematically. You must realize that the mathematical treatment of psionics is, as yet, in a relatively primitive stage." "Oh," Malone said. "Of course. Sure. But this other factor--" "It is what might be called the ... ah ... _volume_ of attention," Dr. O'Connor said. "That is, the actual amount of space that can be conceived of and held by the subject, during the time he is concentrating." Malone blinked. "For most people," Dr. O'Connor said, "the awareness of the space surrounding them is limited to a few inches of moving space, no more. To put this in a purely physical matrix: one might say that the 'teleportation field' doesn't extend more than a few inches beyond the skin of the subject. Thus, it would be difficult to teleport anything really large unless one were able to increase the volume of attention, or awareness. However, it is difficult to express this notion mathematically." "I'll bet," Malone said. * * * * * Dr. O'Connor shot him a frozen glance. "One of our early attempts," he said, "was simply to put this in as a volume factor, so that the left-hand side of the equation, below the line, would read--" He scribbled again on the paper and held it up: m d ---- = K d3ft2 "Unfortunately, as you can perhaps see," Dr. O'Connor said, "the equation would not stand up under dimensional analysis." "Oh, sure," Malone said, adding sympathetically: "That's too bad. But does that put a limit on how much a man could carry with him? I mean, he couldn't take a whole building along, or anything like that, could he?" "I doubt it," Dr. O'Connor said gravely. "That would require a tremendous volume of space for one to focus his entire attention on, as a whole, for any useful length of time. It would require a type of mind that I am not even sure exists." "In the case of a young, inexperienced boy," Malone said stubbornly, "would you say that he could carry off anything heavy?" "Of course not," Dr. O'Connor said. "Nor, as a matter of fact, could he carry off anything that was securely bolted down; I hope you follow me?" "I think so," Malone said. "But look here: suppose you handcuffed him to, say, a radiator or a jail cell bar." "Yes?" "Could he get away?"