In his room at Williamson’s house, Thomas spread the copy of the encrypted message on his table.
The letter had come from Holland and might shed light on the suspected spy ring. If so, and assuming it had been written in English, it might contain such words as England, London, agent, king, or even invasion.
Thomas closed his eyes and tried to visualize the man who had encoded this letter. He saw a middle-aged man, precise in word and dress, an orderly man not given to flights of fancy or expansive gestures. A man in control of himself and his life. A man who wrote in an educated hand with elaborate neatness. There were no corrections that Thomas could discern and the numbers were set out in tidy groups. This was not a man who would use tricks or deliberate mistakes to confuse his enemy but would rely upon his art and technique. He would favour a straightforward cipher. A Caesar, not a Cicero.
He turned his attention back to the message itself and started counting. In decryption much time was spent in counting. There were two hundred and thirty numbers in fifty-seven and a half groups of four. The spaces between groups were certainly irrelevant. No message of this length had ever been written using only four-letter words. Then he counted individual numbers. Ninety-one numbers between 0 and 97 had been used with frequencies varying from seven (28) to one. Numbers 41, 54, 63, 69, 94, 95 and 96 had not been used, either because the letters they represented had not appeared in the plain text message or because they had not been allocated to a letter. The same might be true of numbers 98 and 99. Ninety-seven numbers for a maximum of twenty-six letters meant that at least some letters were represented by more than one number. The question was: had they been allocated randomly or was there some pattern to be found?
All day, without food or drink, Thomas laboured away. By the time his stomach started complaining he had got through ten quills, the floor was littered with discarded papers and his fingers were stained with ink. And he had learned very little. Concentrating on the most frequent numbers – 28, 30, 35 and 46 – he had counted and recounted, attempted a few guesses, tried in vain to gain a foothold by examining the juxtapositions of the numbers, hoping to find two that might represent TH, CH, OU or another common pair, and he had searched in vain for possible vowels and double letters. He had found no hint of pattern. At five o’clock he stood up, stretched his aching back, rubbed his eyes and walked to the window. It was a lovely summer evening and he needed to breathe fresh air. Having carefully locked the door of his room behind him, he let himself out of the house and went for a walk.
Just like Oxford eighteen years ago, he thought, as he made his way towards the new park. Stuck in a room with a wicked cipher, no food, no drink, sore eyes and an aching head. Not to mention Williamson’s displeasure and Morland’s delight if I fail. Why didn’t I hold my tongue and let the wretch try himself? He’d have done no better, the odious toad. Because, whispered Montaigne in his ear, the man who seeks to establish his argument by noise and command shows that his reason is weak. You know Morland’s reason is weak and I expect you to prove it. And you are not alone, replied Thomas silently.
At that time of day the park was busy. Elegant couples in silks and satins strolled beside the canal, noisy children ran about on the grass or played games among the trees, and the king’s gardeners, armed with an array of spades and rakes and hoes, tended His Majesty’s plants. The last time he had been here was with Madeleine and on the very day she had spurned him. The witch. He really had dared to hope that his feelings were shared and that she would be receptive to his advance. Well, at least not as cold as a hoar frost in February, especially after her initial show of warmth. But she’d been playing a game and he’d fallen for it. How else to explain the smile, her arm through his, the compliments, followed only by cruel rejection?
On the west side of the park with the sun behind him, Thomas found a quiet spot under an old oak. His back against its trunk, he sat down and closed his eyes. Oxford, Barbados, back to his quiet life in Romsey, and now where was he? In London, that’s where, up to his neck again in murder and intrigue, desperate to go home, but trapped by his own vanity into attempting to decrypt yet another disobliging encryption. And rejected by the impossible Madeleine Stewart. What might he look forward to next?
‘Enough of this, Thomas,’ he heard Abraham Fletcher say quietly. ‘Get some food inside you and you’ll feel better. Empty your mind and think clearly, just as I taught you, and as you yourself have taught others. Stop feeling sorry for yourself and take some of your own advice. And don’t delay. Morland is counting the hours.’ Thinking that very few teachers have the power to go on teaching long after they are dead, Thomas got to his feet and walked briskly back to Chancery Lane.
Once Williamson’s cook had provided him with an excellent mutton stew, bread and cheese and a bowl of fruit, doubtless brought for her cousin by Miss Stewart, Thomas lay down on the floor and stared at the ceiling. It was an old trick of his – a way of clearing the mind of all unwanted thoughts.
He concentrated on the letter. He still thought Morland was wrong about coded words and syllables, so twenty-six possible letters were represented by ninety-one numbers, with a very even distribution which disguised their normal frequencies. He did not believe that this encrypter had allocated numbers randomly, but systematically, in a way which disguised the letters with particular effect. If Thomas could divine that way he would have taken the first step towards decryption. He went back to the letter and asked himself what he would have done in the encrypter’s place.
Before he could come up with an answer, however, he heard a key turn in the door and in swept Williamson. ‘Good evening, Thomas. What progress have you to report?’
Thomas rose slowly and chose his words with care. ‘I am still sure that Sir Samuel is wrong in believing that it is words and syllables which are represented by the numbers. All my instincts tell me otherwise. But I am not yet in a position to prove it.’
Joseph frowned. ‘Yet? Does that mean progress or no progress?’
‘I have made progress by eliminating a number of possibilities. I know certain things that this cipher is not. I do not yet know what it is.’
‘So should I take your repeated use of the word “yet” as encouraging or not?’
This was becoming uncomfortable. Thomas did not want to lie, but nor did he want to sound less than confident. ‘This cipher can be broken and I will break it. Our enemy is time.’
‘A time, as I recall, Thomas, set by yourself.’
‘Indeed.’
‘And one to which Henry Bishop and I expect you to keep. Neither of us likes Morland but, more importantly, we have the safety of England at stake. Am I clear?’
‘Quite clear, Joseph.’
Williamson’s tone softened, as if he had just remembered that Thomas was fifteen years his senior and was not one of his employees. ‘In that case, is there anything you need?’
‘I shall continue working through the night. If your cook could provide something to sustain me until the morning, I should be grateful.’
‘I will arrange it. Let us hope that the morning will bring better news.’
‘I am confident that it will.’
Once a plate of food and a jug of wine had arrived, Thomas took up a quill and started again. Strangely, it came to him almost at once. This precise, orderly encrypter had allocated numbers according to the frequency with which each letter typically appears, using each allocated number in turn, which would level the distribution. If E were represented by twelve numbers, for example, and appeared thirty-six times in the text, each of its allocated numbers would appear three times. And if D had been allocated four numbers and appeared twelve times, each of its numbers would also appear three times. That was why there were so many repeated numbers and why he had known instinctively that Morland was wrong.
On a new sheet of paper he wrote out the alphabet with the typical weighting for each letter below it. In a standard English text each letter might be expected to appear approximatel
y that number of times relative to all other letters. Twice as many As as Ds, for example. In each row he hoped to be able to compile a list of the numbers the encrypter had allocated to it.
From the hundreds of texts he and Abraham Fletcher had studied thirty years earlier he knew that these frequencies were about right, but only about right. Of course, any single text might throw up anomalies and the rarer letters such as X, Q and Z might not appear at all. He was still working more on instinct than logic, and a liberal dose of Hill’s magic would be needed.
By dawn he had filled dozens of sheets with rows of numbers, his head was protesting and his eyes were closing of their own accord. He had made no more progress and, without rest, he was not going to. He lay down on the floor intending to rest his eyes briefly. Four hours later, however, he was woken by voices outside the door of his room. Rubbing the sleep from his eyes, he pulled himself painfully up on to one elbow and listened.
He recognized her voice at once. ‘Good morning, Joseph. I’ve brought oranges and cherries. They’re delicious. Do try one.’
‘Thank you, my dear.’ Thomas could see in his mind’s eye Williamson reaching out and taking a cherry from her. He struggled to his feet and stretched his back.
‘Is Thomas working here today?’
‘He is, but I’d rather you didn’t disturb him. He’s engaged on a most urgent task.’
‘Oh? What’s that?’
Williamson laughed. ‘You know very well I can’t tell you, Madeleine, and I wouldn’t if I could.’
‘My goodness. It must be very important. Never mind. I only wanted to wish him good day.’
Wish me good day? After showing me the door at her house? What does the witch think I am? Some sort of servant? His hand was on the key and he was on the point of opening the door and confronting her when Abraham spoke again. ‘Leave her, Thomas. Emotion is your enemy. You have work to do.’ To hell with her. He went back to his work table, where there were a few drops of wine left in the jug and a crust of bread on the plate. He swallowed them and took up a quill.
For two hours he worked away at more combinations of numbers, ignoring the spaces between groups and hoping to alight on a clue. If he could find just one possible combination it would be a start upon which he should be able to build.
The start, when it came, was unexpected and thanks to the number 28, which appeared seven times, followed by seven different numbers. He guessed at the letter N, a medium-weight number, followed, at least in some cases, by T. NT was a very common pair – urgent, agent, interest – and likely to appear several times in a text of this length. And T would have about nine numbers allocated to it. The pair also had the characteristic of usually requiring a vowel before the N. From this tentative beginning, he slowly – very slowly and with many corrections – started to ascribe numbers to letters and to write them on his chart. There was no great pleasure in this. He knew that he should have found the letter N sooner. It was Madeleine Stewart’s fault. She had unsettled him.
An exercise like this always reminded Thomas of a race he had once run. Each year on Midsummer’s Day, some of the more athletic scholars had competed for a cask of ale by running ten times around Christ Church Meadow. Naturally they ran as the ancient Greeks had – naked – and there was invariably a good crowd of boisterous onlookers of both sexes. Most of the competitors set off as fast as they could and hoped to get too far ahead for anyone to catch them. They quickly tired each other out. Thomas had won the race easily by starting slowly, accelerating a little in the middle and finishing at a sprint. Complex decryption was much the same. Start too fast and you would regret it later. Take your time and check your work carefully before moving on; and as each letter revealed itself the next one became a little easier.
During the afternoon and evening he found the vowels, then T, S and M. All fatigue disappeared and he was accelerating. At six o’clock he sent for more fuel, gobbled down half a chicken and prepared himself for the final mile.
The mile took longer than expected, however, because there turned out to be as many as twenty-five instances of N, the very first letter he had identified, and only twelve of D, which should have occurred about the same number of times. Reminding himself that if such anomalies did not sometimes occur cryptography would be easy, he continued patiently on his way, until he had a complete list of letters and numbers.
When he was satisfied that the actual number of appearances of each letter was close enough to what he expected, Thomas tried writing out the message. Soon he had:
MONEY DUE FROM ARGENTUM NEEDED IMMEDIATELY. OUR PLANS NOW FAR ADVANCED AND EXPENSES HIGH. RECENT INTELLIGENCE FROM AURUM UNHELPFUL. TAKE URGENT STEPS TO RECRUIT MORE AGENTS. OUR FRIENDS IN FRANCE WILL JOIN US ONLY IF CONFIDENT OF OUR STRENGTH IN ENGLAND. GOD BE WITH YOU. ALCHEMIST.
So the name A. Silver Esq was significant. Argentum and Aurum – silver and gold. And all, it seemed, in the hands of an Alchemist – not, presumably, Ben Jonson’s Alchemist. If proof were needed of a dangerous spy ring run from Holland, here it was. The Dutch and the French. Plans far advanced. More agents. Time to wake the acting secretary of state.
Despite the anticipation of finding out in the morning whether or not Thomas had been successful, Williamson had retired early and was sound asleep when his servant woke him just after midnight. Within minutes he was alert and presentable and down the staircase, where he found Thomas waiting for him, paper in hand.
‘Thomas, good news I trust.’
‘Good news, Joseph, in that I have decrypted the letter. The contents, however, are not so good.’ Thomas handed over the paper. Williamson took it and read it twice.
‘No, not so good, although it might have been worse if you had not decrypted it. The sender of this letter did not expect it to be intercepted and certainly not to be decrypted. It confirms what we have suspected for some months. The Dutch are trying to persuade the French to join them against us, possibly even launch an invasion. The Dutch fleet is already stronger than ours, and if supported by the French . . .’ He let the thought hang in the air.
‘And Argentum and Aurum? Have you any idea who they are?’
‘None. One apparently a source of finance, the other of intelligence. Two traitors acting together against us – one wealthy or with access to wealth, the other with information valuable to our enemies. I am sure the murders of Matthew Smith, John Winter and Henry Copestick were connected to them and that we are dealing with a formidable foe. A ruthless foe who has penetrated our intelligence network. Has Mottershead told you about the rumour of a disfigured foreigner?’
‘He has mentioned it. He said there is talk of the man being the murderer, but there are no witnesses and no clues. It’s merely conjecture.’ Only a white lie, thought Thomas.
‘Quite so. Copestick’s death worries me the most because he worked in the Post Office itself. I know there have always been suspicions about Morland. The man was an ardent republican and has all the charm of a dung heap, but there is not a scrap of hard evidence against him.’
‘What about Squire?’
‘Ha. Too busy stuffing himself, drinking too much and falling ill. Surprisingly clever, but he was never a republican. In fact, like many travelling players, he claims to have carried royalist messages from place to place. I always suspected that was why Cromwell closed the theatres, rather than out of principle. And Squire’s sexual inclinations make him an unlikely Puritan. The theatre was his home and his pleasure. I daresay the precious metals are outside the Post Office after all. The Foreign Office, perhaps.’
‘Perhaps. But there are two of them, it seems. Twice as easy to catch. And what about the Alchemist himself?’
‘As you no doubt know, there are agents scouring Europe for those who signed the late king’s death warrant. I will instruct them to keep their eyes and ears open, but I suspect we’ll only discover the Alchemist’s identity if we can catch Aurum or Argentum and force it out of them. Even then, he’ll be safe in Holland.’ He paused. ‘
I think we will keep this to ourselves for now, Thomas. Much as I would like to see Morland’s face when presented with your decryption, it will be safer if no one else but His Majesty knows that we have read this letter. Meanwhile we will redouble our efforts.’
‘We?’
‘I hope you will assist me, Thomas.’
‘I had intended to return to Romsey immediately.’
‘Immediately? Why so sudden?’
‘I do not care for London. I wish to go home.’ And I wish to persuade my niece to do the same, he thought, before disaster strikes. I have neglected my duty as her uncle and I have no more excuses for doing so.
Joseph peered at him with his good eye. ‘I quite understand. You have done enough. Now I must dress and leave at once to see the king. Go and find a comfortable bed, Thomas. You look as if you need one.’
Thomas awoke in his bed at the Carringtons’ house twenty-four hours later. Just before waking, he had dreamed that Madeleine Stewart was speaking to him in a language he could not understand. The more she spoke the angrier he became, until he picked up a pot of ink and threw it at her. But instead of the ink covering her, it turned itself into letters and numbers which hovered in the air. When he opened his eyes, the room was dark and it took him a minute to remember where he was.
Thomas could never see a summer dawn without thinking of Homer’s ‘rosy-fingered dawn, child of the morn’, and when he looked out of his window, he did so again. A cloudless sky, streaked with red, was lightening as the sun rose, the birds were singing their chorus and the chestnuts in the square were as green as the oaks in the New Forest. A perfect day to begin his journey. In three days he would be home. First, however, he must pay his respects and make his explanations to Charles and Mary, of whom he had seen little since taking on the work for Williamson. More’s the pity. Charles and Mary, quite apart from having saved his life twice, were people he loved dearly. Excellent company, caring, open, honest. The very people a new colony like Barbados needed. Having spent nearly four wretched years on the island, Thomas knew just how demanding a life it was, even for the now-wealthy planters. Disaster lurked around every corner – heat, disease, storms, violence, crop failure – each one could bring a man down and often did. The Carringtons, of course, would take whatever fate threw at them with courage and good humour. That was their way.
The King's Return: (Thomas Hill 3) (Thomas Hill Novels) Page 12