“There is no time to talk,” the girl cut in. “Will you please help me?”
“Gladly. What do you want me to…?” Barney stopped speaking as a faint as happened in ting from the telephone signalled that Haggle had just hung up, and in the same instant the girl disappeared. He turned away from the empty space she had occupied and, more than a little overwhelmed by what had happened, prepared himself to face the mysterious Mr Haggle, squientist and abuser of pretty ghosts.
“Sorry about the interruption,” Haggle said, walking towards the door.
“It’s all right.” Barney gave a hearty laugh to conceal his nervousness. “I really had you going a minute ago, didn’t I? All that nutty stuff about particles looking like snooker balls! Sometimes I let my sense of humour run away with me.”
Haggle’s heavy moustache twitched several times. “You mean, that was a joke?”
“Of course!” Barney spoke quickly, anxious to gain the initiative. “Look, Mr Haggle, I’ve been weighing up your new concept of large-volume particles and I think it’s absolutely brilliant. In fact, I’m so impressed by it that I’m prepared to come and work for you without payment – the privilege of helping in your great work would be all the recompense I would need. What do you say?”
Haggle looked furtively gratified. “You wouldn’t expect any salary at all?”
“Not a penny.”
“And you’ll bring your own lunch?”
Stingy swine, Barney thought. “I’ll bring some for you, as well. My mother is a great cook.”
“Well, in that case,” Haggle said, in the manner of one who was yielding to a generous impulse, “I’m prepared to take you on for a trial period. You can start work immediately.”
“Wonderful!” Barney found it quite easy to sound enthusiastic despite his aversion to work, especially of the unpaid variety. His intention was to remain on the premises only until he had rescued the translucent damsel, and with any luck that task might be completed in a matter of minutes. And as a first step he would have to speak to the girl again and find out exactly why she was unable to pass through the stones of the castle walls like any other spirit. He looked around the shadowed recesses of the room, hoping to catch another glimpse of her, but all the corners and niches remained impenetrably dark.
“…particles, which I have named maryons, can easily penetrate solid screens up to a tenth of a metre in thickness,” Haggle was saying, “but the evidence seems to show that they can be trapped in a container whose walls are more than half-a-metre in thickness.”
“Really?” Barney tried to bring his thoughts to bear on the other man’s preposterous notions about particle physics.
“Yes. And according to my understanding of wave mechanics, that establishes them as objects whose associated wave functions decrease to 0.7 of their full amplitude at about 0.1 metres from their boundary. Do you agree?”
“Absolutely,” Barney said, still covertly scanning his surroundings.
“Their wavelength must be of that order of magnitude – so what sort of rest mass would they have?”
“Huh?” Barney floundered for a moment and then, realizing he would have to play along with Haggle until there was an opportunity to be alone, took a calculator from his pocket and fingered its buttons. “It looks like the rest mass would be less than an electron’s by a factor of around 1016. That’s pretty small.”
“So it wouldn’t take much energy to accelerate a maryon to Earth escape velocity?” Barney did more calculations, all the while wondering at what point Haggle would begin to appreciate the absurdity of his own theories. “Only 10-38 joules.”
A gleam appeared in Haggle’s slightly protuberant eyes. “Would the pressure of the solar wind be enough?”
“More than enough.”
“Hah!” Haggle began to pace the stone floor, his hands fluttering like white moths. “This confirms all my ideas.”
“Does it?” Barney’s wariness of the little man returned as a strange thought began to take shape at the back of his own consciousness. Haggle’s large-volume particles were the product of an eccentric mind, but it was possible to suspend disbelief for a moment and predict that if they did exist they would be very rare on Earth because the solar wind would sweep them away into space. The only places where they might be found would be inside buildings with very thick walls – for example, in the dungeon of an old castle. It looked as though Haggle had come to the same conclusion and had designed his underground laboratory as a sort of bottle for capturing maryons.
Was it possible, Barney wondered with a growing sense of excitement, that Haggle’s arrangement for trapping non-existent particles was also responsible for imprisoning the ghost? If so, all he had to do to set her free was to get Haggle out of the way and open the door. It was all quite simple and straightforward, and yet alarm bells had begun to clamour in Barney’s subconscious, warning him that he had not taken his idea to its logical conclusion, that there were implications he had overlooked. The girl – whose name he had yet to discover – had given him the impression that Haggle was deliberately preventing her escape. And it was odd, very odd indeed, that the postulated physical characteristics of Haggle’s strange particle should be exactly the same as…
“What’s the matter with you, man?” Haggle moved closer to Barney, one of his eyes narrowing critically while the other grew correspondingly larger. “You look like you’ve seen a…”
“I haven’t,” Barney cut in. “I haven’t seen anything.”
“You weren’t listening to a word I was saying.”
“It’s just that I’m rather tired,” Barney said. “Haven’t slept much lately. Worrying about not getting a job.”
Haggle scowled his dissatisfaction. “I have to go upstairs for a while. Can I trust you to familiarize yourself with the equipment and not fall asleep as soon as I leave?”
“Of course,” Barney said eagerly, pleased at the prospect of being alone with his ghost-girl. He hurried to one of the benches and stared fixedly and conscientiously at the instruments on it until Haggle left. As soon as the door had swung shut behind the little man Barney turned and walked towards the dark area where he had last seen the ghost. She appeared to him almost immediately and he felt an upsurge of tenderness and concern as he saw that she was more distraught than ever.
“You mustn’t worry,” he soothed. “I’ll get you out of here in no time. You’ll see.”
She shook her head. “I can scarcely believe it. After being bricked up in a cell for almost three hundred years I have begun to feel that I shall never escape.”
“Bricked up in a cell!” Barney was horrified. “Who did that to you?”
“My uncle – Lord Cyril.”
“But what made him do such a terrible thing?”
The girl lowered her gaze. “I fancied myself in love with a stableboy. My uncle said that if I could not find it within myself to behave like a lady it was incumbent on him to remove me from all worldly temptation by locking me in the castle dungeon.”
Barney felt a twinge of jealousy towards the long-dead stablehand and was at once consumed by intense curiosity about how far the affair had progressed. Unable to think of a diplomatic way of obtaining the information, he asked the girl’s name and was told that it was Mary Grey. Further questioning revealed that Mary had died of pneumonia soon after her incarceration and that her uncle, who probably had not intended things to go that far, had hidden his misdeed by having her cell bricked up. Mary’s ghost had been imprisoned there for almost three centuries – until Haggle had knocked the wall down in the course of constructing his laboratory.