Equinox

'And that worked?'

'Like a dream.

'So there's another scytale.'

'Problem was, though, I just had the same ninety-eight numbers — the seven rows of fourteen. I tried to see if there were any obvious patterns that popped up, you know — numbers one to seven or something straightforward like that, but that didn't work.'

'So what did you do?' Laura asked.

'I wasted a good hour chasing up a blind alley looking at number relations, like doubling the first number — 3.5, 7, 14 — I'm sure Charlie did that deliberately to throw people off the scent. But, after I realised that this was going nowhere, I started to think about the other part of the message — the colours. That's where Dad helped out.'

'I can do more than make the coffee,' Philip said.

'Glad to hear it. This tastes awful,' Laura retorted, pulling a face. 'Just kidding … Go on.'

'Dad was on the computer trying to find out anything he could about the alchemy stuff that Charlie had described, and I was at the table over there using reliable old pen and paper.'

'By happy coincidence, just as Jo got stuck I found out some stuff about the emerald tablet and what alchemists tried to do with the inscriptions on it. There is absolutely nothing on the Net about the ruby sphere, but I guess you would expect that.'

'Come on, then. Tell me. What did you find?' Laura asked impatiently.

'Pretty crazy, most of it,' Philip replied. 'There was no consistency in the work of the alchemists. They were all obsessed with secrecy. You can see why Charlie was attracted to this stuff. It was all about codes and secret languages, one alchemist keeping secrets from another. They certainly didn't like to share, and they each interpreted their findings differently. More often than not the accounts they left of what they discovered contradict each other completely. However.' He took a deep breath and rubbed his eyes. 'There were a few things they all had in common. First, they all started their experiments with a simple set of chemicals which they mixed together and heated to see what would happen. Second, almost all alchemists used the emerald-tablet texts as their source of information; and from this they followed a sort of "recipe". In almost all accounts, they saw the same thing happen when they heated their mix of chemicals. They saw them change colour. The pattern was always the same — the mixture started off black, turned white, then yellow, then red.'

'Ah.'

'Ah indeed,' Philip said.

'Still didn't get me anywhere,' said Jo, with a grin. 'Except that it made me focus on the colours in Charlie's message, and how they might relate to the table of numbers — Charlie was obviously tying them together. In cryptanalysis everything has a purpose, and Charlie is — was — a master.'

'OK, so what did you do?'

'Nothing much, just stared at the cylinder of numbers,' Jo said. 'And then suddenly I saw it.'

'Saw what?'

'The numbers 5,5,6,3 in one of the columns along the scytale.'

'The word black — five letters, white — five letters, and so on?' Laura asked.

'Precisely. And that, Mother, is called a key.'

'Well, thanks, Jo. I'm not Homer Simpson.'

'The block of text is a set of instructions,' Philip interrupted. He showed Laura a printout.

FIRST OFF. USE THE SAME KEY TO DECODE NEWTON'S DOCUMENT. INTERPRET THE INCANTATION — IT MIGHT INTEREST YOU. THE DIAGRAM SHOWS THE LABYRINTH UNDER THE BODLEIAN. YOU ENTER IT VIA THE TRILL MILL STREAM, DOOR IN WALL SIXTY-THREE PACES IN FROM WEST ENTRANCE. AT THE BOTTOM OF THE

PAGE IS AN ESSENTIAL QUOTE: YOU WILL NEED IT LATER. GOOD LUCK!

'Fantastic, Jo!' Laura exclaimed. 'OK. My turn.' She jumped up from the sofa. 'Newton document, Philip, please,' she said. 'And lots more of your excellent coffee.'

Laura laid out the single page on the table in the dining room. Charlie had used a high-res colour photocopier and every crease and crinkle of the original could be seen on the reproduction. It had a dark ochre tinge and was skirted with white where Charlie had mounted the document on a modern card backing. The lettering was in different shades of grey. Laura assumed that Newton had used different inks and added to the text over a period of time. Around the edges of the page were roughly drawn diagrams and images, symbols and formulae. Laura wondered about the significance of a ram's head, a sun symbol and a few Greek letters. .

At the top it said: PRINCIPIA CHEMICUM by Isaacus Neuutonus and beneath that were two lines of Latin.

'The subtitle is just about the only thing that makes any sort of immediate sense,' said Laura, leaning over the paper with her arms crossed on the table. 'I read that much in the car coming from London.'

'It does?' Philip and Jo said in unison.

'God, where were you two educated? It says "From the Manuscript of the Adept Ripley and Supplemented by My Own Researches and Explorations. Translated from the Original Egyptian Text.'"

The rest of the page was divided almost evenly into two. The first section consisted of lines of writing, made up from a block of letters similar to the text that Charlie had put on the DVD. Under that was a roughly drawn scratchy-looking diagram — a network of interlocking lines that resembled a complex maze of corridors. At the base of the diagram a series of lines threaded their way almost to the foot of the page. Beside this was a single line in plain Latin:

ALUMNUS AMAS SEMPER UNICIUM TUA DEUS

'Over to you again, Mom,' Jo remarked wearily.

'Yes, it's a bit of an odd sentence. Literally, it translates as: "Pupil love always. . er, uniquely, I guess.. thy, your.. God." Which is very clumsy, so I suppose it would better read as something like: "Adept", yes, adept is better for alumnus … "Adept, love always thy God.'"

'"Adept, love always thy God"? A sort of signing-off? A signature at the end of the document?' Philip speculated.

'Could be. Perhaps a sort of general statement for the alchemist, like "God Bless You" or "Best Wishes", maybe.' Laura shrugged. 'Doesn't seem to help much. Let's get to work on this first block, using the key'

'5 5 6 3,' Jo said. 'So, fifth letter, tenth, sixteenth, nineteenth.'

As they went methodically through the text Philip wrote down each letter on a fresh sheet of paper. After a few minutes they had distilled nine lines from it.

'It's Latin again,' Laura noted. 'I can translate the first few words, but there are no breaks.'

After twenty minutes, between them they had arranged the string of letters into a paragraph of Latin words which Laura translated and wrote out on a separate sheet.

You are Mercury the mighty flower, You are most worthy of honour; You are the Source of Sol, Luna and Mars, You are Settler of Saturn and Source of Venus, You are Emperor, Prince and most regal of Kings, You are Father of the Mirror and Maker of Light. You are head and highest and fairest in Sight. All praise thee.

All praise thee. Giver of truth.

We seek, we beseech, we welcome you.

'Twaddle,' Philip snorted.

'Maybe, but it's obviously some sort of incantation. I can only assume this is what the Order of the Black Sphinx use to conjure up Old Nick.'

'And this is what the present-day Order need to carry out the ritual.'

'And what Charlie gave them in altered form,' Philip said.

'Why did he bother changing it if it's all nonsense?' Jo asked.

'Because he's a believer. Never quite understood how someone so intelligent could be taken in by this stuff, but there you are. To Charlie, this incantation was a real way to conjure up the Devil, and to the members of the Order it is too. Newton believed it — but then, he did live in an entirely different age, an era during.which magic and witchcraft were accepted in the way that we accept the principles of science.'

'They can believe in the Loch Ness Monster for all I care,' Philip added. 'But we have to do everything we can to stop them committing more murders. And we have just over twelve hours before the next one.'