I knew, not for the first time, that my friend had done the impossible. This was Sherlock Holmes at his best and most invincible, doing something that no other man on earth could have done. He stood with his back to the fireplace as he read out the list. When we came to the end, he sat down again and spoke as if he feared it was too good to be true.
âThose numerals, Watson! Identical and in the same sequence throughout the cipher and the document! It is thousands to one against mere coincidence.'
âBut what is the Admiralty document you have been reading figures from?'
âThe design calculations for the latest and most powerful battle cruiser of all, HMS
Renown
. By the pricking of my thumbs, I knew they would be after information such as this!'
He sat at the table for a moment and then turned to me again.
âLook at this dockyard manifest. It is a list of weights when the battle cruiser is fully loaded. All the tonnages in the right-hand column correspond to the numerals in Henschel's signal. An entire sequence of fifty! It must be the same document. Very well. If that column of figures is correct, then each of Henschel's double-digit code words on the left-hand side must describe the item whose weight appears on the right. See here. We have our decoded numerals for weight on the right. They stand opposite two unknown words in Henschel's code, the first being 46-24-47. The word in the Admiralty list at this point is “General” in “General Equipment.” Therefore 46-24-47 in Henschel's code surely stands for “General,” in whichever language. You see?'
I began to see but he was not to be stopped.
âAnd here again. Against the entry for “3335 tons,” the word in the Admiralty document is “Armament.” Henschel encodes this as 25-80-13-24-59. We know that the Ashmolean Museum can put sounds to Linear B syllables. In English, these five double digits must sound something like “Ar-ma-me-n-t.” Thus five of the eighty-seven syllables of the alphabet are revealed! The syllables before “5660 tons” must match “Machinery.” Before “120 tons” the numerical syllables, if one may call them that, must encode “Engineer's Stores.”'
By evening, ignoring the tray that Mrs. Hudson brought, Holmes had broken what secret Admiralty files still refer to as the Linear B code. Dr. Gross had not translated his ciphers into German but simply encoded whatever he received. No doubt an elderly scholar of ancient languages may quail before engineering terminology. Holmes had deciphered every numerical sign for weights, the load calculations for HMS
Renown
. Matching the words of each item to its known tonnage, he pieced together the German code of Dr. Gross's ancient Mycenaean âalphabet.' He found that 80-41-24-53 must stand for â
MACHINERY
,'
SO
that 24 stood for â
NE
.' He confirmed it in the next line where 18-46-24-27 must be â
ENGINEER
,' for 24 was â
NE
' in both cases. It was the same throughout the document and, indeed, in all the other coded signals. Our enemies had never varied the basic Linear B code, so sure were they that it could never be overcome.
By next morning Holmes had equivalents for seventy of the eighty-seven letters of the word code, as well as all the numerals. Whether the learned Dr. Gross exactly copied the symbols of King Minos five thousand years agoâor varied them to suit his masters' purposeâSherlock Holmes had him by the tail as surely as Theseus ever had the Minotaur.
As if to confirm this, the next transcript to reach us from the Admiralty contained a page opening with the familiar sequence of double digits 57-09-83-62-15 || 19-80-05. I checked the pencilled note I had made at the time and found that it was identical to the opening of the cipher written on the paper that Dr. Gross had left in the stool rack of the Ashmolean Museum. This time the message had nothing to do with armaments but, rather, with the time required to gather Class A Naval reservists at Chatham and other ports of the Thames estuary, in the event of general mobilization and impending war.
7
Not many months after this, on a hot summer day in the far-off dusty Balkan town of Sarajevo, two bullets from the gun of a Bosnian student shot dead the Archduke Franz Ferdinand of Austria and his duchess. It was well said that the bullet that killed the heir to the throne of Austria-Hungary was a shot that echoed round the world. At the time, I confess, I could not have believed that this Balkan outrage, shocking though it was, would precipitate a war unparalleled in human history. Yet there was no longer any doubt that the blindfold war that Holmes and I waged against unseen adversaries was in earnest. Our Baker Street rooms resembled more and more a battlefield. Several times that summer, during the remaining weeks of peace, Sherlock Holmes was absent for the entire day on a visit to the Admiralty. His business was with a mysterious group of people known only as Room 40.
In the wake of our Linear B discoveries came Superintendent Alfred Swain of the Special Branch. That branch was created at the time of the Fenian explosions in the 1880s and had originally been known as the Special Irish Branch. Before long it concerned itself with every kind of threat to the security of the nation. One afternoon, when Baker Street was a trench of white summer fog and the street lamps popped and sputtered at noon, was the first time that this Special Branch officer was our guest. The clatter of a barrel organ serenaded us from the opposite pavement with âTake me on the Flip-Flap, oh, dear, do,' as coins rattled into the grinder's cap.
The Special Branch may consist of hard, resolute men well able to take care of themselves, yet Superintendent Swain was a tall, thin figure, neatly but plainly suited. He spoke quietly and, as he sat down, he turned an intelligent equine profile and gentle eyes toward us. Inspector Lestrade had warned us scornfully what to expect from a man who read Lord Tennyson's
Idylls of the King
or Mr. Browning's translation ofthe
Agamemnon
âor even Tait's
Recent Advances in Physical Science
and Lyell's
On Geology
. There had been a movement among his colleagues to get rid of Alfred Swain by posting him to the Special Branch. He was thought by his CID superiors to be âtoo clever by half.' He certainly gave the impression of a man who would rather have come to tea to discuss the novels of Mr. George Meredithâone of Sherlock Holmes's unaccountable enthusiasms. Holmes took to him from the start. As his grey eyes studied my friend intently, Swain picked his words carefully, almost fastidiously.
âMr. Holmes, it must be said at the outset that you have lately performed a service to your country such as few men have done for many years past. Thanks to you, we now have Dr. Gross and Herr Henschel where we want them.'
Holmes looked alarmed.
âNot under arrest, I hope? I have had Sir John Fisher's word on that.'
Swain shook his head.
âNo, sir. The First Sea Lord has kept his word. Indeed, you have given us an invaluable advantage in this. We are now reading their coded signals. But before we can take the matter further, we must identify the third member of their conspiracy, presumably at the Admiralty. When that is accomplished, we shall endeavor to turn their stratagem against them, rather than throw them into prison. Thanks to you, we have the means in our hands to save the lives of hundreds of our soldiers or sailors in the event of war, even to save our country from defeat.'
âI am relieved to hear it,' Holmes said, indifferent to such flattery. âAnd what have you done to identify the traitor in the Admiralty?'
âBoth Dr. Gross and Henschel are closely watched. From their method of procedure, it seems that Henschel probably knows nothing of the spy's identity. It is possible that neither of them does. Henschel appears to be a mere technician who transmits whatever is given him. Each man works, as it were, in a watertight compartment. None of them, if he were caught, could betray any part of the conspiracy but his own.'
âBut you have connected their movements together?'
Swain sat back in his chair and folded his hands across his waistcoat.
âWe have had Dr. Gross under observation. He uses no telephone. He has sent two wires, both of which we have read. They were directed to the librarian at the British Museum, requesting certain books to be brought up from the stacks for Dr. Gross's visit. He also receives a small amount of post, three communications in the past five weeks.'
âYou have opened those envelopes, Mr. Swain?'
âWe are aware of their contents, sir,' said Swain evasively. âApart from Henschel and Dr. Gross, there is the man whom I will call the naval spy. There appear to be twenty-four people at the Admiralty, from senior officers to junior clerks, who might have taken the design calculations of HMS
Renown
from the building in order to copy them. We have had them all under observation for some weeks and they have made no evident contact with either Dr. Gross or Mr. Henschel. Yet during that time, in the present international tension, the coded German signals have been transmitted almost nightly. We do not believe that Henschel can be transmitting from his rooms. Yet the signals are going out from somewhere near Sheerness, no doubt to a German naval vessel or trawler in the North Sea.'
At this point Swain took a notebook from his pocket and began to read a list of the information transmitted in the past few weeks.
âParticulars of Armament:
Indefatigable
Class. Particulars of Anti-Torpedo Boat Guns, 4-inch and 6-inch. HMS
Princess Royal:
replacement of nickel steel, armour diagram. Comparison of Boiler Weights and Performance in HMS
Inflexible
, boiler by Yarrows, Ltd., and HMS
Indomitable
, boiler by Babcock & Wilson. I understand, gentlemen, that Yarrow boilers are lighter and would allow
Indomitable's
six-inch armor to be increased to seven inches without affecting her speed.'
Alfred Swain paused, then added.
âThat is a sample of the technical information passing to our adversaries. More recently there have also been manoeuvre reports, gunnery ranges, torpedo matters, fire control, and signals. Last week, for the first time, there were answers to questions that Henschel must have received. Which parts of the fleet have been in the Firth of Forth since the beginning of Mayâthe First and Eighth Destroyer Flotillas or any ships else? Have there been mobilizing tests of flotillas or coastal defences? What numbers of the Royal Fleet Reserve Class A reservists are called in for the yearly exercise?' Swain paused and looked at us. âAll these are details vital to the other side in any immediate preparations for war.'
Holmes crossed to the window, drew aside the net curtain, and looked down into the thin summer fog. It was possible to see across the street, and no doubt, though the barrel organ was still rattling out its tunes, he satisfied himself that the movements of our visitor were not under observation by our enemies.
âTell me about Dr. Gross, Mr. Swain.'
Swain looked a little uncomfortable.
âThere is little to tell, sir. He was an archaeologist as a younger man, with Schliemann at the discovery of Troy, and then deputy keeper of antiquities at the Royal Museum in Berlin. He has lived quietly as a retired gentleman in Beaumont Street for the past two years. He goes out either to the Ashmolean or to work in one of the libraries. He takes lunch at the Oxford Union Society, of which he is a member. That seems to be his only social contact. He retires early to his rooms until the next day. In the past five weeks he has visited London each Monday and stayed for one night at the Charing Cross Hotel. He leaves each morning after breakfast and walks up the Charing Cross Road to the British Museum.'
âWho watches him?'
âHe works all day in the North Library, Mr. Holmes, where I have kept him companyâat a distance. He speaks only to the assistants and leaves at five thirty. He dines early at an Italian café in Holborn, then walks back to the hotel by eight
P
.
M
. One of my colleagues is already dining at the café when he arrives. Dr. Gross speaks only to the waiter and returns direct to the hotel. Whoever the spy in the Admiralty may be, it seems he does not write to Dr. Gross, or speak to him, or communicate by telegram or telephone. We have watched the old man every minute, so far as we can. There appears to be no dead letter box except the hollow frame of the rack of camp stools in the Ashmolean Museum. Dr. Gross uses that only to leave the encoded messages for Henschel. It is possible that Henschel does not know the code and, though a member of the conspiracy, does not know precisely what the signals contain when he transmits them.'
Holmes sighed deeply.
âI ask myself, if I were Dr. Gross, how would I manage it? Easily enough, I believe. There are so many ways! I daresay I would receive a letter at the Oxford Union Society. I understand it is run like a gentlemen's club, where there is a very large green baize board next to the porter's desk, crisscrossed with wire. Any letter through the post or a message by hand may be inserted there and left until the member collects it. The place is reserved to members only and you might keep observation outside for a month of Sundays without knowing what goes on inside.'
Swain looked a little embarrassed.
âOne of our plain-clothes officers has walked through that corridor and scanned the letter board every morning. There is never a letter for Dr. Gross.'
âHe may use another name and collect the letter even so.'
âMr. Holmes,' said Swain quietly, âthere are dozens, scores, of letters sent there every day. We cannot open them all, under every name, without giving the game away. In any case, he might as easily receive a letter at the Charing Cross Hotel, under any name.'
Holmes seemed to change tack.
âPrecisely. Then it must be a matter of observationâthe most tedious of occupations. Yet it seems evident that Dr. Gross receives his information in London. Communication evidently does not take place between the time he leaves the hotel and the time he returns, unless something is slipped between the pages of a book on a British Museum shelf and he obtains it from there.'