The direction which M. Stepark followed would take him through the northern part of the town, while his policemen, in pairs, were going through the centre.Captain Haralan and I would proceed along the banks of the Danube.

The weather was overcast.Large grey clouds were rapidly chasing one another from the east, and, under the fresh breeze, the boats were furrowing the yellowish waters of the river.Pairs of storks and cranes, heading into the wind, were uttering piercing cries.It was not raining, but the lofty clouds threatened to burst into a torrential downpour.

Except in the commercial quarter, then filled with a crowd of townsmen and peasants, the passers-by were few.But if the Chief and his men had come with us it might have attracted attention, and it was better for us to separate as soon as we left the Town Hall.

Captain Haralan again kept silent.I was still afraid that he was not master of himself, and that if he were to meet Wilhelm Storitz he would give vent to some act of violence.For this reason I almost regretted that M.Stepark had let us accompany him.

A quarter of an hour was enough for us to reach the corner on which stood the Doctor's house.None of the ground floor windows was open, nor were those of the room occupied by Madame Roderich and her daughter.What a contrast with the liveliness of the previous night!Captain Haralan stopped, and his glance flew for a moment to those closed shutters.A sigh escaped him, he made a menacing gesture, but he never said a word.

Having gone round the corner, we went up the Boulevard Tékéli, stopping near the home of Wilhelm Storitz.A man was carelessly walking up and down in front of the gate, his hands in his pockets.It was the Chief of Police.Captain Haralan and I joined him as had been arranged.

Almost at once there appeared six plainclothes policemen.At a sign from M.Stepark, they lined up in front of the railings.With them was a locksmith, brought in case the gate refused to open.

The windows were closed as usual, and the curtains of the belvedere were drawn, making them opaque.

‘There can't be anybody in, 'I told M.Stepark.

‘That's what we're going to find out, 'he replied.‘But I should be surprised if the house were empty.Look at that smoke coming from that chimney, that one on the left.'

And indeed, a wisp of sooty smoke was rising above the roof.

‘If the master isn't at home, 'M.Stepark added, ‘the servant is likely to be, and for letting us in, it doesn't matter if it's the one or the other.'

For my part, considering that Captain Haralan was present, I should have preferred Wilhelm Storitz to be absent, and even for him to have left Ragz.

The Chief of Police thundered at the knocker fixed on to an iron plate on the railings.Then we waited for someone to appear or for the gate to be opened from the inside.

A minute elapsed.Nobody.A second blow on the knocker.

‘They've got deaf ears in this house.'M.Stepark murmured.Then, turning towards the locksmith, ‘Get on with it, 'he said.

The man chose a tool from his set, the picklock was thrust into the keyhole, and the gate opened without difficulty.

The Chief of Police, with Captain Haralan and myself, entered the yard.Four of the policemen accompanied us, the other two staying outside.

A flight of three steps led to the door of the house, closed like the yard gate.

M.Stepark knocked three times with his walkingstick.

There was no response, and no noise came from within the house.

The locksmith went up the steps and thrust one of his keys into the lock.This might possibly have been doubly or trebly locked, or the door might have been bolted on the inside, if Wilhelm Storitz.after seeing the policemen, had tried to keep them from entering.

But nothing of the sort.The lock gave, and the door at once opened.

‘Let's get in, 'said M.Stepark.

The corridor was lighted by the grill of the fanlight above the door, and at its far end by the glass window from a second door which gave access to the garden.

The Chief of Police took a few paces down the corridor and shouted, ‘Is anybody in?'

No reply, even when the shout was repeated more loudly.No noise came from the interior of the house.At least, by straining our ears and listening very attentively, we thought we could catch a sort of gliding sound in one of the side rooms……But this was an illusion, no doubt.

M.Stepark went right down the corridor.I walked behind him, and Captain Haralan followed me.

One of the policemen had stayed on guard on the steps.

The door open, we could at once see the whole of the garden.It was walled in, and in its centre was a lawn which had not been scythed for a long time, and whose long grass was lying half-withered on the ground.Around it ran a winding path bordered by a fairly thick shrubbery.Behind this could be seen some tall trees, no doubt planted along the walls, and whose heads seemed to dominate the epaulements of the neighbouring fortifications.

Everything denoted complete negligence.

The garden was searched.The policemen could find nobody in it, though there were recently-made footmarks on the paths.

On this side the windows were closed by outside shutters, except for the last on the first floor, which lighted the stairs.

‘It can't have been long since those people came in.'commented the Chief of Police, ‘for the door's only locked and hasn't been bolted……If only they haven't taken warning and made themselves scarce!’

‘Do you think they could have known?'I asked.“No.I think it's more likely they'll come in any time now.'

M.Stepark shook his head doubtfully.

‘Anyhow, 'I added, ‘that smoke coming out through one of the chimneys shows that there's a fire somewhere.'

‘Find that fire!'ordered the Chief of Police.

After making certain that the garden was as deserted as the yard, and that there was nobody hidden in it, M.Stepark asked us to go back into the house, and the door was shut behind us.

This corridor served four rooms.In one of them, next to the garden, somebody had been doing some cooking.Another opened on to the stairway which rose to the first floor and then to the attic.

It was in the kitchen that the search began.On of the policemen opened the window and threw back the shutters;these were pierced by a small lozenge-shaped opening, which had let in very little light.

Nothing could be more simple and rudimentary than the furniture of that kitchen—an iron stove, whose chimney vanished under the hood of an immense hearth;on each side a cupboard;in the middle a table;two cane chairs and two wooden stools;a few utensils hanging from the walls;and in a corner a grandfather clock which ticked regularly, and whose weights showed that it had been wound up the evening before.

In the stove were still burning some fragments of coal;this had produced the smoke we had seen outside.

‘Here's the kitchen, 'I said, ‘but where's the cook?'

‘And his master?'added Captain Haralan.

‘We'll keep on looking, 'M.Stepark replied.

The other two rooms on the ground floor, which were lit from the yard, were visited in order.One, the drawingroom, was set out with furniture of ancient work, their upholstery of German origin being very badly worn.On the mantlepiece, above the great andirons, was an ornamental clock in rather bad taste;its motionless hands and the dust on its face showed that it had not been going for a long time.On one of the walls, facing the window, was hanging a portrait in its oval frame, with the name on a scroll:OTTO STORITZ.

We looked at that portrait, bold in design and crude in colouring, and signed by an unknown artist, a real work of art.

Captain Haralan could not tear his eyes from that canvas.

For me, the face of Otto Storitz impressed me deeply.Was this due to the state of my mind……Or rather was I giving way, unconsciously, to the influence of my surroundings?However that might be, here, in this empty room, the savant appeared like a creature of phantasy.With that massive head, that dishevelled hair, that lofty forehead, those glowing eyes, that mouth with lips that seemed to quiver, I felt that the portrait was alive, that it was going to leap out of its frame, and to cry like a voice from another world:

‘What are you doing here?Who is rash enough to disturb my rest?'

The window, closed by Venetian blinds, let in a little light.There had been no need to open them, and in that comparative darkness the portrait may have seemed even stranger and even more impressive.

The Chief of Police seemed struck with the resemblance between Otto and Wilhelm Storitz.

‘But for the difference in age, 'he told me, ‘that portrait might have been just as much that of the son as of the father.They've got the same eyes, the same forehead, the same head set upon those great shoulders……And that diabolical expression!I feel tempted to have them both exorcised.'

‘Yes, 'I agreed, ‘there's a surprising resemblance.'

Captain Haralan appeared to be nailed to the floor in front of that canvas, as though its original had been in confronting him.

‘Are you coming, Captain?'I asked.

We went along the corridor into the room next door.This was the workshop, completely in disorder.Whitewood shelves, cluttered with volumes most of which were unbound, the majority of them works on mathematics, chemistry and physics.In a corner a number of instruments, apparatus and contrivances, a portable furnace, a few retorts and alembics and several specimens of metals, some of which, engineer though I am, were new to me.In the middle of the room, on a table loaded with papers and other writing materials, three or four volumes of the complete works of Otto Storitz.Beside them, a manuscript.Bending over it, I saw that, signed with the same celebrated name, it was a treatise on optics.

The search carried out in this room had no other result which could help us.We were about to leave it when M.Stepark caught sight of a blue-tinted phial of bizarre shape standing on the mantlepiece.

Whether it were to satisfy a feeling of curiosity or his detective instincts, he stretched out his hand to grasp it, so as to examine it more carefully.But he must have made some blunder, for the phial, which was on the edge of the mantlepiece, fell just as he was about to grasp it, and smashed on the floor.

A thin liquid of a yellowish colour escaped from it.Extremely volatile, it was at once converted into a vapour with a strange smell which I cannot compare to anything else, although it was so feeble that I could barely detect it.

‘Well, 'exclaimed M.Stepark, ‘it fell just at the proper time, that phial did.'

‘No doubt, 'I commented, ‘it contains some preparation invented by OttoStoritz.'

‘His son will have the formula, 'M.Stepark replied, and he'll be able to make more of it.'Then, turning towards the door, ‘On to the first floor, 'he added, and he told one of his men to wait in the corridor.'

Here, facing the kitchen, was the door leading to a staircase with a wooden handrail;its steps creaked under our feet.

On the landing two rooms opened side by side.Their doors were not locked, and we only had to turn the copper door-handle to get into them.

The first must have been Wilhelm Storitz'bedroom.All it contained was an iron bedstead, a bedside table, an oak linen-cupboard, a toilet-table on copper legs, a couch, an armchair in thick velvet, and two chairs.No curtains to the bed, no curtain to the windows;the furniture was plainly reduced to the bare necessities.No documents, neither on the mantlepiece nor on the small round table in one of the corners.The bed was still unmade at that early hour, but presumably it had been slept in during the night, as we might reasonably assume.

On examining the toilet-table, M.Stepark noticed that the basin contained some water, with soap-bubbles floating on its surface.

‘If, 'he pointed out, ‘twenty-four hours had elapsed since somebody used that water, those bubbles would have dissolved.From which I infer that our man made his toilet here, this morning, before he went out.'

‘So it's possible he'll come back?'I replied, ‘at least so long as he doesn't see your men.'

‘If he sees my men, my men will see him, and they've got orders to bring him in.But I don't think he'll let himself be caught.'

At that moment we heard a sound like the creaking of a badly-adjusted floor-board which had just been trodden on.This noise seemed to come from the room next door, above the workshop.

There was a door communicating with that room, which obviated our going back to the landing to get into it.

Ahead of the Chief of Police, Captain Haralan reached that door in one bound and flung it open.

But we had made a mistake.There was nobody there.

It was after all possible that the noise had come from the room above, from the attic which led to the belvedere.

That second room was even more simply furnished than the first;a frame supporting a length of strong canvas, a mattress much flattened by use, some thick blankets, a woollen coverlet, a jug of water and a sandstone basin on the mantlepiece of a hearth which did not disclose the smallest trace of cinders, some articles of coarse clothing, and an oak coffer in which M.Stepark found a fair quantity of household linen.

This room was evidently that of the old servant Hermann.The chief of Police pointed out, too, that if the window of the first room was sometimes opened to let in the air, that of the second, which likewise opened on to the yard, was invariably shut.We could verify this when we examined the window-fastening, which was very stiff, and the iron-work of the shutters, which was eaten with rust.

Anyhow, this room was empty.If this were also true of the attic, the belvedere, and the cellar beneath the kitchen, master and servant must have left the house, and they might mean never to come back.

‘You don't suppose, 'I asked M.Stepark, ‘that Wilhelm Storitz has got wind of this investigation?'

‘No, Monsieur Vidal, unless he'd hidden himself in my room or in that of his Excellency when we were discussing this business!'

‘When we came into the Boulevard, it's just possible they may have seen us.'

‘Maybe—but how would they have got out?'

‘By getting into the open country at the back.'

‘They wouldn't have had time to get over the garden wall, which is so very high.What's more, on the other side there's the moat of the fortifications, and nobody could cross that.'

He was of the opinion that Wilhelm Storitz and Hermann were already outside the house before we got into it.

Another minute and we had reached the second floor.

This consisted only of the attic which stretched from one gable-end to the other.It was lighted by two narrow skylights let into the roof, and one glance was enough to show us that nobody had taken refuge there.

In the centre a rough ladder led to the belvedere which dominated the roof.Its interior was reached by a trap-door swinging on a counterweight.

‘That trap-door is open.'I commented to M.Stepark, who had already put one foot on the ladder.

‘Yes, Monsieur Vidal, and there's quite a draught coming down through it.That must have made the noise we heard.There's a strong wind today, and the weathercock is creaking on the top of the roof.'

‘But, 'I point out, ‘we should have said it was the sound of footsteps.'

‘Then who could have been walking, as there's nobody here?'

‘Unless he's up there, M.Stepark?'

‘In that aerial nest?'

Captain Haralan had been listening to our conversation.He contented himself with pointing to the belvedere and saying, ‘Come on up.'

M.Stepark was the first to mount the rungs, with the help of a thick cord hanging down to the floor.Captain Haralan next, then myself, we climbed after him.It seemed quite likely that three people would be enough to fill that narrow room.

It was, in fact, nothing but a sort of cage measuring eight feet by eight, and about ten feet high, and it was fairly dark, although a sheet of glass was set between the uprights which supported the beams of the ridge.This darkness was due to the thick woollen curtains having been drawn, as we had noticed from outside.But as soon as they were thrown back, the light flooded in through the glass.

The belvedere was just like the rest of the house.We could not find anybody in it.So although M.Stepark had done his work, this swoop of the police had produced no result, and we still knew nothing about any of the mysteries which the house might contain.

I had imagined that the belvedere might serve for astronomical observations, and that it might contain apparatus for studying the sky.I was mistaken.The only furniture was a table and a wooden armchair.

On the table were a number of papers, and among them the copy of the newspaper which had informed me, at Budapest, about the approaching anniversary of Wilhelm Storitz.These papers were seized, like the others.

It was obviously here that the son had rested on coming out of his workshop, or rather his laboratory.Anyhow, he had read that article, which was marked, certainly by his hand, with a red-ink cross.

All at once a violent exclamation was heard, an exclamation of angry surprise.

Captain Haralan had noticed, on a shelf fixed to one of the uprights, a cardboard box which he had just opened……

And what had he taken out of the box……

The nuptial crown which had been carried off the evening before from Dr.Roderich's home!