‘The bang, Mr. Holmes. I was at the back, where the maid was taking out the clothes from the washhouse to dry on the line. I was just tipping out ashes from the grate of the copper. Then there was a flash that lit up the window of the upstairs back room—Mr. Henshaw’s study—brighter than day and a bang that rattled every windowpane in the street. My first thought was the gas fire had gone up. Seeing Mr. Lethbridge patrolling the street, I rushed out and called him. He ran back and went up the stairs first and I went up behind him. I half expected to find poor Mr. Henshaw stone-cold dead. But there he was, sitting on a chair, just looking a bit shocked. And the strange thing was—after such a bang that might have wrecked the entire house, not a thing in the room seemed harmed.’
‘Curious,’ said Holmes gently.
‘It was curious all right. Ever so sorry, he was. Went to light the gas fire and it somehow blew back. Only thing is, Mr. Holmes, there was no match that had been struck, the fire wasn’t lit, and there was no smell of gas. But there was a horrible smell of something else. Till that moment I never really thought about it, but I think I smelt it up there before, from time to time, only not so strong. Anyway, that was the end of it. Mr. Lethbridge went back to his beat and I suppose Mr. Henshaw went back to reading French. Then, last night, there was a knock at the door and I’m told I’m wanted at Scotland Yard today.’
If my friend felt any excitement at this, he concealed it admirably under an appearance of casual interest.
‘Tell me about the flash, Mrs. Constantine. Did it at all resemble the bright flash you see when the metal poles of a tramcar cross a connexion?’
‘Now you mention it, sir, it was just like it. That hadn’t occurred to me.’
Holmes stood up and walked past the worktable to a jumble of books, papers, bottles, and implements on an old sideboard. He came back with a small six-sided clear-glass bottle and drew the stopper from it.
‘Will you tell me, Mrs. Constantine, whether the smell that you say was not like gas was anything like this? You need not get too close to it, just enough to be able to smell. Just smell and do not inhale.’
He held it at a little distance and waited until the fumes drifted across to her. Mrs. Constantine gave a slight cough, screwed her face up, and exclaimed, ‘Ugh! Nasty, beastly stuff! What he wanted with it I do not know. But that’s it, sir.’ She took a long sip from her cup of tea.
‘Perhaps, Mr. Holmes,’ said Lestrade, ‘you might let us into your little secret.’
‘I have no secret, Lestrade. What Mrs. Constantine could smell was sulphuric acid.’
‘What’s he doing with sulphuric acid?’ the inspector asked suspiciously.
‘What’s he doing short-circuiting a battery, Lestrade, and a fully charged battery at that, on a Monday morning? Tell me, Mrs. Constantine, does your Congregational chapel have electric light?’
‘I think its Sunday school hall does. That was only built three or four years back.’
‘Then I daresay that is how he charges his accumulator battery—and why it was fully charged on Monday morning. Tell me a little about this nice young lodger of yours. Does he travel much, for example? Abroad, perhaps?’
She laughed at him.
‘Lord bless you, Mr. Holmes, I shouldn’t say he’d been further abroad than the end of Margate pier. No. He does go to Oxford every week or two, on a Saturday, to buy books for his French.’
‘Rather odd, is it not, that he should not buy them in London, so much closer?’
‘Well, you see, Mr. Holmes, I was given to understand that he has a friend he meets in Oxford. They take tea together.’
‘Ah,’ said Holmes, ‘that must be it. One more question, dear lady. From what part of the country does he come?’
Mrs. Constantine looked troubled and then replied,
‘I don’t know that I could say, Mr. Holmes. Not from round our way, I should think. He talks quite like a gentleman, that’s all.’
‘Very good.’ My friend looked thoroughly satisfied. ‘One more word, Mrs. Constantine. I am quite sure you have nothing to fear from the young gentleman. The police are merely looking for unusual occurrences over a very wide area—is that not so, Lestrade?—and that is the sole reason you have been troubled. This is clearly nothing more than a trivial domestic mishap. You will continue to allow him to lodge with you, shall we say for the next six months? He seems, after all, an admirable tenant in every other way.’
‘I can’t say as I know about that,’ she said with a slight coloring of indignation.
‘I do not believe you will have further cause for complaint, but I must have your promise upon this. Nor must you say a word to him or anyone else about our conversation. I must have your solemn promise upon that, too.’
She hesitated and I intervened.
‘Perhaps you have a sister or a friend with whom you might care to stay for a few weeks, until the upset of this has worn off. Provided the maid could look after Mr. Henshaw.’
‘I might, sir. However it may be, you shall have my promise for the next six months. As to what has passed between us here, mum’s the word.’
To meet Mrs. Constantine was to know that the promise would be kept. She was the type to sweep Napoleon and his invaders out of England with a broom and a bucket. As our visitors left, it was only Lestrade who seemed in a fit of the sulks, piqued that he was not to be let further into the secret.
Holmes was jubilant. He was not a man much given to wine, but that evening we shared a bottle of Dom Perignon, one of six dozen presented to him several years before by a client and as yet untasted.
The next morning there was no sign of him. He was not an early riser, and until I inquired of our landlady’s maid-of-all-work, I had supposed he was still sleeping. His room was empty and my day passed idly but agreeably, a day chiefly remarkable for the autumn’s first flurry of snow. At six o’clock I heard his shout to Mrs. Hudson on the stairs. He was back.
‘I thought you had gone missing,’ I said, half joking.
He flung down his hat and stick on the chair; his cloak followed.
‘My dear Watson, I have spent the day in that most admirable of institutions, Somerset House. In painted halls and palatial apartments, enjoying unrivalled views of the river steamers on the Thames, one may study the records of births, marriages, and deaths to one’s heart’s content.’
‘Whose birth, marriage, or death?’
‘No one’s. There is a far smaller section where those who have changed their names by deed poll are obliged to register the fact. I confess that the name Charles Henshaw sounded to me like—what shall we call it?—a light adaptation of something else. I was not entirely surprised to find that at Chatham Registry Office—not a million miles from Sheerness—it was adopted several years ago by Karl Henschel.’
‘A German?’
‘I confess, I should have thought so. In this case, when he changed his name, he was already an Englishman, or rather a German who had become a naturalised Englishman on a visit to Australia. You could hardly bury a secret much deeper than that.’
‘But Mrs. Constantine has not the least doubt that he is English, through and through.’
‘He is a linguist, my dear chap. A German linguist, particularly, will often speak more correct English than an Englishman born and bred. As for teaching French to English youths—or English to French youths—what better cover could there be? You might suspect him, perhaps, of being French by birth or sympathies. If he were German, you might say, the last thing he would do is to teach French in England.’
‘And his Saturday visits to Oxford, what about those?’
‘We shall be at Paddington tomorrow for the early train. On my way home, I paid a brief visit to Scotland Yard. Whitehall and the Embankment looked quite charming in the snow, quite like a Camille Pissarro sketch in oils. Superintendent Melville has deputed Inspector Tobias Gregson to shadow Herr Henschel, as we had better call him now. Gregson is one of the best men at the game. Even were Henschel to suspect that he was being followed, he would see that Gregson had slipped away from him in London. At Paddington I shall look for Gregson on the platform for the Oxford trains. He will tip us the wink, as they say, and identify Henschel. I have our man’s photograph this afternoon, taken without his knowledge yesterday. Then, my dear Watson, Gregson will be on his way and the game will be in our court again.’
‘You may as well pack your razor and a clean collar,’ said Holmes at breakfast. ‘I have wired ahead to engage rooms at the Mitre Hotel. I daresay it may prove an unnecessary precaution, but it is as well to be prepared. Your army revolver you may bring if you please. I cannot suppose it will be necessary on this occasion.’
Saturday morning had dawned bright and cloudless as mid-summer, giving the lie to ‘drear November.’ Under his travelling cloak, Holmes wore a dark suit with a gold watch-chain over the waistcoat. This formal attire was scarcely what a lounger would choose for a weekend. As our cab rattled along the Marylebone Road toward Paddington station, I could not help wondering what our spy might look like. Would Karl Henschel be the bearded agent of romance or merely a young man who might be mistaken for an insurance clerk? One thing seemed certain, he could not be the traitor in the Admiralty. Sir John Fisher had assured us that there was no Charles Henshaw on their records.
At Paddington the concourse of the great railway station was bustling with weekend travelers crowding about the bookstall, the flower-sellers, and the cab ranks. Columns of smoke rose to the high curve of the glass roof from several green-liveried engines of the Great Western Railway waiting to depart. There was no train at the platform for Oxford and only a handful of passengers waiting by the leather trunks and wicker hampers, neatly piled for the luggage van.
It was hardly twenty minutes later when I recognized Gregson in his pale gray topcoat and bowler hat, keeping well back from his quarry. He scarcely needed to ‘tip us the wink.’ From where we stood it was quite plain to see who his quarry was. I should have taken the young language teacher for an army subaltern on weekend leave, neatly turned out in a belted Norfolk jacket and twill trousers, a black leather bag at his side. Slightly built, clean-shaven and with short-cropped hair, he had an air of peremptoriness about him.
The young man’s back was to us as Holmes looked Gregson in the eyes at a distance of several yards and inclined his head an inch or so. Our Scotland Yard friend in his gray topcoat walked past us as though we had been strangers and disappeared on the far side of the bookstall. We made our way to the further end of the platform, which would bring us close to the exit when the train reached Oxford.
It did not seem that Henschel was accustomed to spend the night in Oxford but would return to Sheerness by a train that would leave for London in the late afternoon or early evening. At our destination, however, we had already arranged for a hotel porter to take our travelling bags from us and carry them to the Mitre Inn.
There was no difficulty in finding a compartment to ourselves on the journey. A dreary hour of West London was followed by enchanting views of the Thames valley running among the winter woods of the hills with flooded water-meadows to either side. It was not yet midday when we saw from the railway line the spires and towers of the ancient city.
The station approach at Oxford was lined by luggage wagons and cabs, but Henschel crossed the road and began making his way toward the centre of the town on foot. We kept well back, walking separately, until he turned up the wide thoroughfare of Beaumont Street with its plain but handsome houses. The creeper-covered windows and archway of one of the colleges faced us from the far end. I was as sure as I could be that our man had no idea he was being followed. He did not once look back or make any manoeuvre to suggest that he was trying to throw off a shadow. Our only risk was that an accomplice lay further back, trailing us in turn. Yet there was no sign of such a man, and he would have been astute indeed if he had been able to shadow Sherlock Holmes unobserved!
I was conscious that every stretch of open street or pavement increased the danger of Henschel spotting us. I need not have worried. At the top of Beaumont Street he turned into the wide courtyard of the Ashmolean, the university museum, which was raised on a plinth with its Grecian portico, pillars, and statues, a sculptured goddess sitting high above a classical frieze. As the corner concealed us briefly, I drew level with Holmes and said, ‘For all we can tell, he may have come like any other tripper to see the collections. It seems more than likely.’
We separated again, two visitors dutifully and individually making our tour of the exhibits. The museum was admirably laid out for the purposes of tracking our suspect. Tall display cases running across the galleries make admirable cover for the hunter, yet one step beyond them gives a wide view ahead and behind. To begin with, from our concealment among the displays of classical sculpture on the ground floor, we watched Henschel go up the grand staircase leading to the galleries above.
Holmes waited until the young man had turned the corner to the second flight of steps and then walked slowly after him. I saw my friend pause and begin studying a dark van Eyck landscape on the half-landing. He had his back to the flight of stairs up which Henschel had gone to the floor above. Yet as Holmes stood there, I could see that in the palm of one hand he held a small round pocket mirror, reflecting the stairs behind him and the gallery above.
I followed cautiously up the staircase, well lit by its roof lights, to the wide and airy exhibition hall of the first floor. Before me lay a vista of Italian Renaissance art, to which we and our quarry were the only visitors just then, except for two ladies talking quietly together and a middle-aged gentleman on his own. There were display cases ranked in the center of the gallery and paintings along the walls to either side. I am no expert in such matters, but the small brass plates on each frame identified for me two Botticelli sketches of nymphs in woodland and a dimly lit papal portrait by Fra Lippo Lippi. How such things could be connected with espionage and naval codes defied explanation.