As regards the item, I apologize for taking so long to respond, but I wanted to be sure I had collated the results from all concerned. The upshot is that we are well and truly stumped.
As you specified, we did not breach or penetrate the glass casing of the sphere, so all our tests were noninvasive in nature.
On the matter of the radioactivity, no harmful emissions registered when it was tested — so at least I can put your mind at rest on that one.
A metallurgist carried out an MS on a microscopic shaving from the base of the metal cage, and he agreed with your view that it's Georgian. He thinks the cage is made out of pinchbeck, which is an alloy of copper and zinc invented by Christopher Pinchbeck (1670–1732). It was used as a substitute for gold and only produced for a short while. Apparently, the formula for this alloy was lost when the inventor's son, Edward, died. He also told me that genuine examples of this material are scarce, and it's hard to find an expert who can give an unequivocal identification. Unfortunately, I haven't yet been able to get the cage carbon dated to confirm its precise age — maybe next time?
What is particularly interesting is that an x-ray revealed a small, free-floating particle in the center of the sphere itself that does not alter its position even after rigorous agitation — this is puzzling, to say the least. Moreover, from a physical inspection, we agree with you that the sphere appears to be filled with two distinct liquid factions of differing densities. The turbulence you noted in these factions does not correspond to temperature variations, internal or external, but is unquestionably photoreactive — it only seems to be affected by a lack of light!
Here's the rub: The crew over in the chemistry department have never seen anything like it before. I had a fight on my hands to get it back from — they were dying to crack the thing open in controlled conditions and run a full analysis. They tried spectroscopy when the sphere was at its brightest (at maximum excitation its emissions are in the visible spectrum — in layman's terms, not far off daylight, with a level of UV within acceptable safety parameters, and the «liquids» appeared to be predominately helium — and silver-based. We can't make any more progress on this until you allow us to open it.
One hypothesis is that the solid particulate at the center may be acting as a catalyst for a reaction that is triggered by the absence of light. We can't confirm how, at this juncture, or come up with any comparable reactions that would occur over such a long period of time, assuming the sphere really does date from the Georgian era. Remember, helium was not discovered until 1895 — this is at odds with our estimate for the date of the metal casing.
In short, what we have here is a conundrum. We would all very much welcome a visit from you for a multifaculty meeting so that we can schedule a program for further analysis of the item. It may even be useful for some of our team to drop into Highfield for a quick investigation into the background.
I look forward to hearing from you.
With kindest regards,
Will put the letter on the table and met Rebecca's stare. He examined the sphere for a moment, then went over to the light switch and, shutting the door to the kitchen, flicked off the lights. They both watched as the sphere grew in brightness from a dim greenish luminescence to something that indeed approached daylight, all in a matter of seconds.
"Wow," he said in wonder. "And they're right, it doesn't even feel hot."
"You knew about this, didn't you? I can read you as easily as a comic book," Rebecca said, staring fixedly at Will's face, which was lit by the strange glow.
Will didn't respond as he turned on the lights but left the door shut. They watched as the sphere dulled again. "You know how you said no one was doing anything about finding Dad?" he said eventually.
"So?"
Chester and I came across something of his and we've been… making our own inquiries."
"I knew it!" she said loudly. "What have you found out?"
"Shh," Will hissed, glancing at the closed door. "Keep it down. I'm certainly not going to bother Mum with any of this. Last thing I want to do is get her hopes up. Agreed?"
"Agreed," Rebecca said.
"We found a book Dad was keeping notes in — a sort of journal," Will said slowly.
"Yes, and…?"
As they sat at the kitchen table, Will recounted what he had read in the journal and also their encounter with the strange pallid men outside the Clarke's shop.
He stopped short of telling her about the tunnel under the house. To him, that was just a little secret.
17
It was a week later when Will and Chester finally made the breakthrough. Dehydrated from the heat at the work face, and with muscles that were cramped and fatigued by the relentless cycle of digging and tipping, they were on the verge of wrapping up for the day when Will's pickax struck a large block of stone and it tipped backward. A pitch-black opening yawned before them.
Their eyes locked onto the hole, which exhaled a damp and musty breeze into their tired and dirty faces. Chester 's instincts screamed at him to back away, as if he were about to be sucked into the opening. Neither of them said a word; there were no great cheers or exultations as they gazed into the impenetrable darkness, with the dead calm of the earth all around them. It was Chester who broke the spell.
"I suppose I'd better be getting home, then."
Will turned and looked at him with incredulity, then spotted the flicker of a smirk on Chester 's face. Filled with an immense sense of relief and accomplishment, Will couldn't help but erupt into a peal of hysterical laughter. He picked up a clod of dirt and hurled it at his grinning friend, who ducked, a low chuckle coming from beneath his yellow hard hat.
"You… you…" Will said, searching for an appropriate word.
"Yeah, what?" Chester beamed. "Come on, then, let's have a look-see," he said, leaning into the gap next to Will.
Will shone his flashlight through the opening. "It's a cavern… Can't make out much in there… Must be pretty big, I think I can see some stalactites and stalagmites." Then he stopped. "Listen!"
"What is it?" whispered Chester.
"Water, I think. I can hear water dripping." He turned to Chester.
"You're kidding," Chester said, his face clouding with concern.
"No, I'm not. Could be a Neolithic stream…"
"Here, let me see," said Chester, taking the flashlight from Will.
Tantalizing as it was, they decided against any further excavation there and then. They would rйsumй the following day when they were fresh and better prepared. Chester went home; he was tired but quietly elated that their work had borne fruit. It was true that they were both badly in need of sleep, and Will was even, unusually, considering taking a bath as he swung the shelves back into position. He did the usual sweep-up and made his way lethargically upstairs to his room.
As he passed Rebecca's door, she called out to him. Will grimaced and held as still as a statue.
"Will, I know you're out there."
Will sighed and pushed open her door. Rebecca was lying on her bed, where she'd been reading a book.
"What's up? asked Will, glancing around her room. He never ceased to be amazed at how infuriatingly clean and tidy she kept it.