The next day, accordingly, I presented myself, half expecting to be hurled into the midst of a formal levee, surrounded by petitioners and claimants all wanting the attention of a man close to the court. There were indeed a few people there, but not many and they were ignored. I concluded from this that Mr. Bennet’s star had not yet risen too far or, for reasons of his own, he was keeping his connections, and even his presence in London, fairly quiet.
I cannot say that he was pleasant; indeed, he had a formality of manner which verged on the grotesque, so keen was he to observe all the niceties of protocol, and maintain rankings in a clear form. It came, I believe, from spending too long in Spain, which is notoriously prone to such excesses. He took the trouble to explain to me that he had provided a chair with a padded seat, as befitted my dignity as a doctor of the university; others, it seemed, had to make do with a hard seat or remain standing, depending on their station. It would have been unwise of me to hint that I considered such punctiliousness absurd—I did not know what he wanted and the government was about to send a visitation to the university to eject members inserted by the Commonwealth. As I had been so inserted, Mr. Bennet was not a man to annoy. I wanted to keep my position.
“How do you consider the state of His Majesty’s kingdom?” he said abruptly, not being a man to waste too much time putting his guests at ease or winning their confidence. It is a trick often played by men in power, I find.
I replied that all His Majesty’s subjects were naturally delighted at his safe return to his rightful throne. Bennet snorted.
“So how do you account for the fact that we have just had to hang another half dozen fanatics for plotting against the government?”
“ ‘This is an evil generation,’ “ I said. (Luke 11:29.)
He tossed a sheaf of papers over to me. “What do you think of those?”
I looked at them carefully, then sniffed dismissively.”Letters in cipher,” ï said.
“Can you read them?”
“Not at the moment, no.”
“Could you read them? Tease out their meanings?”
“Unless there is some particular difficulty, yes. I have had some considerable experience in such matters.”
“I know that. For Mr. Thurloe, was it not?”
“I provided no information which might have injured the king’s party, even though it was in my power to do it considerable harm.”
“Are you now prepared to do it any good?”
“Of course. I am His Majesty’s loyal servant. I trust you remember that I took great risks with my fortune in protesting against the murder of the late king.”
“You satisfied your conscience in the matter, but not to the point of leaving office, or turning down preferment when it was offered, I recall,” he replied coldly, and in a manner which gave me little optimism about winning his favor. “No matter. You will be pleased at the opportunity of demonstrating how great your loyalties are. Bring me those letters deciphered tomorrow morning.”
And so I was dismissed, not knowing whether to bless my luck or curse my misfortune. I went back to the inn where I habitually stayed in London—this was before I acquired my house in Bow Street on the death of my wife’s father—and settled down to work. It took all day, and most of the night, to get the letters done. The art of decipherment is a complicated one, and was getting more so. Frequently it is simply a matter of figuring out how one letter or group of letters was replaced by another—you work out by substitution that (for example) “a” stands for “the,” 4 stands for king, d=l, f=d, h=on, g=i, v=s, c=n; and it is simple enough to decide that a4gvgcdhfh means that the king is in London. You will note that while the method (much favored by the Royalists in the war, as they were, I’m afraid to say, rather straightforward souls) of substituting one letter for another is simple, the method of making a letter occasionally substitute for a letter, and occasionally for a syllable or a word, is more difficult. Nonetheless, it still presents few problems. What is more difficult is when the value attached to the letters constantly changes—a method first proposed in England by Lord Bacon but, I understand, in fact invented by a Florentine over a hundred years ago and now claimed by the French, an insolent nation which cannot abide that anything should not come from their land. They steal that which is not theirs; I suffered myself when a wretched little clerk called Fermat dared to say my work on indivisibles was his own.
I will try to explain. The essence of this method is that both sender and recipient must have the same text. The message begins with a group of numbers which reads (say) 124, 5—meaning that the key begins on page 124, word five, of this text. Let us suppose that this page begins—“So Hatach went forth to Mordecai unto the street of the city, which was before the king’s gate.” (Esther 4:6, a puzzling text on which I have given an elucidatory sermon, shortly to be published.) The fifth word, “to,” is your starting point, and you substitute “t” for “a,” thus getting an alphabet:
so that your message, “The king is in London,” now reads “maxdbgzblbgehgwhg.” The important thing is that, after a given number of letters, normally twenty-five, you move to the next word, in this case Mordecai, and start again, so that m=a, n=b and so on. Variations on this method exist, of course. But the point is to ensure that the value of letters changes sufficiently frequently for it to be all but impossible to make the code out unless you have the text on which it is based. I will explain why this was important later on.
I was worried that the scripts given me might be of this type; I could possibly have deciphered them eventually, but not in the time allowed. If I am vain about my abilities, it is with some justice; only one text has ever defeated me, and that was in special—though important—circumstances which I will deal with later. But every time I am handed a coded letter, I know that bitter experience of failure might be mine once more, for I am not infallible and the possible variant combinations are virtually infinite. I myself have constructed codes which are unreadable without the right texts for decipherment, so it was perfectly possible that others could do so as well; indeed I am surprised that I have not been defeated more often, as it is easier to construct an impregnable code than it is to breach its walls. Fortunately, in the case of Mr. Bonnet’s letters I was again lucky—the authors were as simple-minded in their approach as were the Royalist conspirators in their day. Few people, I find, are prepared to learn from experience. Each epistle had a different code, but they were simple ones and each was long enough to allow me to fix the meanings. At seven the next morning, accordingly, I presented myself once more to Mr. Bennet, and handed over my labors.
He took them, and glanced over the fair copy I had prepared. “Would you summarize them for me, doctor?”
“They appear to be a group of letters to one individual, probably in London,” I said. “All specifying a date, January twelfth. There are references in two of them to weapons, but not in the others. One mentions the kingdom of God, which I imagine rules out papists, and indicates that the authors are Fifth Monarchists or groups associated with them. Internal evidence suggests two of the letters come from Abingdon, which also indicates a seditious origin to the letters.”