Burgess, locked in the windowless luggage van, knew by now the location of the train at any moment by the sound of the track. He heard first the smooth clacking of the wheels on the well-laid rails of the yard. Then, later, the hollow, more resonant tones as the train crossed Bermondsey on the elevated overpass for several miles, and, still later, a transition to a deader sound and a rougher ride, signaling the beginning of the southward run outside London and into the countryside.

Burgess had no inkling of Pierce's plan, and he was astonished when the coffin bell began to ring. He attributed it to the vibration and sway of the train, but a few moments later there was a pounding, and then a muffled voice. Unable to make out the words, he approached the coffin.

"Open up, damn you," the voice said.

"Are you alive?" Burgess asked, in tones of wonderment.

"It's Agar, you damnable flat," came the answer.

Burgess hastily began to throw the catches on the coffin lid. Soon after, Agar-- covered in a dreadful green paste, smelling horrible, but acting in normal enough fashion-- got out of the coffin and said, "I must be quick. Get me those satchels there." He pointed to the five leather valises stacked in a corner of the van.

Burgess hurried to do so. "But the van is locked," It said. "How will it be opened?"

"Our friend," Agar said, "is a mountaineer."

Agar opened the safes and removed the first of the strongboxes, breaking the seal and taking out the dull gold bars of bullion-- each stamped with a royal crown and the initials "H amp; B." He replaced them with small bags of sewn shot, which he took from the valises.

Burgess watched in silence. The train was now rumbling almost due south, past the Crystal Palace, toward Croyden and Redhill. From there it would go east to Folkestone.

"A mountaineer?" Burgess said finally.

"Yes," Agar said. "He's coming over the tops of the train to unlock us."

"When?" Burgess said, frowning.

"After Redhill, returning to his coach before Ashford. It's all open country there. Almost no chance of being seen." Agar did not glance up from his work.

"Redhill to Ashford? But that's the fastest part of the run."

"Aye, I suppose," Agar said.

"Well, then," Burgess said, "your friend is mad."

At one point in the trial of Pierce, the prosecutor lapsed into a moment of frank admiration. "Then it is not true," said the prosecutor, "that you had any experience of the recreation of mountaineering?"

"None," Pierce said. "I merely said that to reassure Agar."

"You had not met Mr. Coolidge, nor read extensively on the subject, nor owned any of the particular devices and apparatus considered vital to that activity of mountaineering?"

"No," Pierce said.

"Had you, perhaps, some past experiences of athletic or physical endeavor which persuaded you of your ability to carry out your intended plan?"

"None," Pierce said.

"Well, then," said the prosecutor, "I must inquire, if only for reasons of ordinary human curiosity, what on earth, sir, led you to suppose that without prior training, or knowledge, or special equipment, or athletic prowess-- what on earth led you to believe you might succeed in such a palpably dangerous and, may I say, nearly suicidal undertaking as clambering about on a swift-moving railway train? Wherever did you find the audacity for such an act?"

Journalistic accounts mention that at this point the witness smiled. "I knew it would be no difficulty," he said, "despite the appearance of danger, for I had on several occasions read in the press of those incidents which are called railway sway, and I had similarly read of the explanation, offered by engineers, that the forces are caused by the nature of swiftly moving air as shown in the studies of the late Italian, Baroni. Thus, I was assured that these forces would operate to hold my person to the surface of the coach, and I should be utterly safe in my undertaking."

At this point, the prosecutor asked for further elucidation, which Pierce gave in garbled form. The summary of this portion of the trial, as reported in the Times, was garbled still further. The general idea was that Pierce-- by now almost revered in the press as a master criminal-- possessed some knowledge of a scientific principle that had aided him.

The truth is that Pierce, rather proud of his erudition, undertook his climb over the cars with a sense of confidence that was completely unfounded. Briefly, the situation was this:

Beginning around 1848, when railway trains began to attain speeds of fifty or even seventy miles an hour, a bizarre and inexplicable new phenomenon was noted. Whenever a fast-moving train passed a train standing at a station, the carriages of both trains had a tendency to be drawn together in what was called "railway sway." In some cases the carriages heeled over in such a pronounced fashion that passengers were alarmed, and indeed there was sometimes minor damage to coaches.

Railway engineers; after a period of technical chatter, finally admitted their perplexity outright. No one had the slightest idea why "railway sway" occurred, or what to do to correct it. One must remember that trains were then the fastest-moving objects in human history, and the behavior of such swift vehicles was suspected to be governed by some set of physical laws as yet undiscovered. The confusion was precisely that of airplane engineers a century later, when the "buffeting" phenomenon of an aircraft approaching the speed of sound was similarly inexplicable, and the means to overcome it could only be guessed at.

However, by 1851 most engineers had decided correctly that railway sway was an example of Bernoulli's Law, a formulation of a Swiss mathematician of the previous century which stated, in effect, that the pressure within a moving stream of air is less than the pressure of the air surrounding it.

This meant that two moving trains, if they were close enough, would be sucked together by the partial vacuum of air between them. The solution to the problem was simple, and soon adopted: the parallel tracks were set farther apart, and railway sway disappeared.

In modern times, Bernoulli's Law explains such diverse phenomena as why a baseball curves, why a sailboat can sail into the wind, and why an airplane wing lifts the aircraft. But then, as now, most people did not really understand these events in terms of physics: most jet-age travelers would probably be surprised to learn that a jet flies because it is literally sucked upward into the air by a partial vacuum over the wings' upper surface, and the sole purpose of the engines is to propel the wings forward fast enough to create a stream of passing air that produces this necessary vacuum.

Futhermore, a physicist would dispute even this explanation as not really correct, and would insist that a rigorous explanation of events is even further from the public's "common sense" idea about these phenomena.

In the face of this complexity, one can readily understand Pierces own confusion, and the erroneous conclusion. he drew. Apparently he believed that the airstream around the moving carriage, as described by "Baroni," would act to suck him down to the carriage roof, and thus help him to maintain his footing as he moved from car to car.

The truth is that Bernoulli's Law would not operate in any way on his body. He would simply be a man exposed to a fifty-mile-an-hour blast of rushing air, which could blow him off the train at any moment, and it was absurd for him to attempt what he did at all.

Nor was this the extent of his misinformation. The very fact that high-speed travel was so new left Pierce, along with his contemporaries, with very little sense of the consequences of being thrown from a fast-moving vehicle.

Pierce had seen Spring Heel Jack dead after being thrown from the train. But he had regarded this with no sense of inevitability, as the outcome of some inexorable physical laws. At this time, There was only a vague notion that to be thrown from a speeding train was hazardous, and somewhat more hazardous if the train was moving rapidly. But the nature of the hazard was thought to lie in the precise manner of a person's fall: a lucky man could pick himself up with a few scrapes, while an unlucky man would break his neck on impact. In short, a fall from a train was regarded pretty much like a fall from a horse: some were worse than others, and that was that.

Indeed, during the early history of railroads, there had been a sort of daredevil's sport called "carriage-hopping," favored by the kind of young men who later scaled public buildings and engaged in other madcap escapades. University students were particularly prone to these amusements.

Carriage-hopping consisted of leaping from a moving railway carriage to the ground. Although government officials condemned the practice and railway officials flatly forbade it, carriage-hopping enjoyed a brief vogue from 1830 to 1835. Most hoppers suffered nothing more serious than a few bruises, or at worst a broken bone. The fad eventually lost popularity, but the memory of it bolstered the public belief that a fall from a train was not necessarily lethal."

In fact, during the 1830s, most trains averaged twenty-five miles an hour. But by 1850, when the speed of trains had doubled, the consequences of a fall were quite different, and out of all proportion to a fall at slower speeds. Yet this was not understood, as Pierce's testimony indicates.

The prosecutor asked: "Did you take any manner of precaution against the danger of a fall?"

"I did," Pierce said, "and they caused me no little discomfort. Beneath my ordinary external garb, I wore two pairs of heavy cotton undergarments, which had the effect of making me unpleasantly heated, yet I felt these protective measures necessary."

Thus, wholly unprepared and entirely miscalculating the effects of the physical principals involved, Edward Pierce slung a coil of rope over his shoulder, opened the compartment door, and clambered up onto the roof of the moving carriage. His only true protection-- and the source of his audacity-- lay in his complete misunderstanding of the danger he faced.