'There is no danger, I promise you,' said Arthur gently. 'We are going to find out the meaning of all this mystery.'

He began to walk towards the house.

'Have you a weapon of some sort?' asked the doctor.

Arthur handed him a revolver.

'Take this. It will rea.s.sure you, but you will have no need of it. I bought it the other day when--I had other plans.'

Susie gave a little shudder. They reached the drive and walked to the great portico which adorned the facade of the house. Arthur tried the handle, but it would not open.

'Will you wait here?' he said. 'I can get through one of the windows, and I will let you in.'

He left them. They stood quietly there, with anxious hearts; they could not guess what they would see. They were afraid that something would happen to Arthur, and Susie regretted that she had not insisted on going with him. Suddenly she remembered that awful moment when the light of the lamp had been thrown where all expected to see a body, and there was nothing.

'What do you think it meant?' she cried suddenly. 'What is the explanation?'

'Perhaps we shall see now,' answered the doctor.

Arthur still lingered, and she could not imagine what had become of him.

All sorts of horrible fancies pa.s.sed through her mind, and she dreaded she knew not what. At last they heard a footstep inside the house, and the door was opened.

'I was convinced that n.o.body slept here, but I was obliged to make sure.

I had some difficulty in getting in.'

Susie hesitated to enter. She did not know what horrors awaited her, and the darkness was terrifying.

'I cannot see,' she said.

'I've brought a torch,' said Arthur.

He pressed a b.u.t.ton, and a narrow ray of bright light was cast upon the floor. Dr Porhoet and Susie went in. Arthur carefully closed the door, and flashed the light of his torch all round them. They stood in a large hall, the floor of which was scattered with the skins of lions that Haddo on his celebrated expedition had killed in Africa. There were perhaps a dozen, and their number gave a wild, barbaric note. A great oak staircase led to the upper floors.

'We must go through all the rooms,' said Arthur.

He did not expect to find Haddo till they came to the lighted attics, but it seemed needful nevertheless to pa.s.s right through the house on their way. A flash of his torch had shown him that the walls of the hall were decorated with all manner of armour, ancient swords of Eastern handiwork, barbaric weapons from central Africa, savage implements of medieval warfare; and an idea came to him. He took down a huge battle-axe and swung it in his hand.

'Now come.'

Silently, holding their breath as though they feared to wake the dead, they went into the first room. They saw it difficultly with their scant light, since the thin shaft of brilliancy, emphasising acutely the surrounding darkness, revealed it only piece by piece. It was a large room, evidently unused, for the furniture was covered with holland, and there was a mustiness about it which suggested that the windows were seldom opened. As in many old houses, the rooms led not from a pa.s.sage but into one another, and they walked through many till they came back into the hall. They had all a desolate, uninhabited air. Their sombreness was increased by the oak with which they were panelled. There was panelling in the hall too, and on the stairs that led broadly to the top of the house. As they ascended, Arthur stopped for one moment and pa.s.sed his hand over the polished wood.

'It would burn like tinder,' he said.

They went through the rooms on the first floor, and they were as empty and as cheerless. Presently they came to that which had been Margaret's.

In a bowl were dead flowers. Her brushes were still on the toilet table.

But it was a gloomy chamber, with its dark oak, and, so comfortless that Susie shuddered. Arthur stood for a time and looked at it, but he said nothing. They found themselves again on the stairs and they went to the second storey. But here they seemed to be at the top of the house.

'How does one get up to the attics?' said Arthur, looking about him with surprise.

He paused for a while to think. Then he nodded his head.

'There must be some steps leading out of one of the rooms.'

They went on. And now the ceilings were much lower, with heavy beams, and there was no furniture at all. The emptiness seemed to make everything more terrifying. They felt that they were on the threshold of a great mystery, and Susie's heart began to beat fast. Arthur conducted his examination with the greatest method; he walked round each room carefully, looking for a door that might lead to a staircase; but there was no sign of one.

'What will you do if you can't find the way up?' asked Susie.

'I shall find the way up,' he answered.

They came to the staircase once more and had discovered nothing. They looked at one another helplessly.

'It's quite clear there is a way,' said Arthur, with impatience. 'There must be something in the nature of a hidden door somewhere or other.'

He leaned against the bal.u.s.trade and meditated. The light of his lantern threw a narrow ray upon the opposite wall.

'I feel certain it must be in one of the rooms at the end of the house.

That seems the most natural place to put a means of ascent to the attics.'

They went back, and again he examined the panelling of a small room that had outside walls on three sides of it. It was the only room that did not lead into another.

'It must be here,' he said.

Presently he gave a little laugh, for he saw that a small door was concealed by the woodwork. He pressed it where he thought there might be a spring, and it flew open. Their torch showed them a narrow wooden staircase. They walked up and found themselves in front of a door. Arthur tried it, but it was locked. He smiled grimly.

'Will you get back a little,' he said.

He lifted his axe and swung it down upon the latch. The handle was shattered, but the lock did not yield. He shook his head. As he paused for a moment, an there was a complete silence, Susie distinctly heard a slight noise. She put her hand on Arthur's arm to call his attention to it, and with strained ears they listened. There was something alive on the other side of the door. They heard its curious sound: it was not that of a human voice, it was not the crying of an animal, it was extraordinary.

It was the sort of gibber, hoa.r.s.e and rapid, and it filled them with an icy terror because it was so weird and so unnatural.

'Come away, Arthur,' said Susie. 'Come away.'

'There's some living thing in there,' he answered.

He did not know why the sound horrified him. The sweat broke out on his forehead.

'Something awful will happen to us,' whispered Susie, shaking with uncontrollable fear.

'The only thing is to break the door down.'

The horrid gibbering was drowned by the noise he made. Quickly, without pausing, he began to hack at the oak door with all his might. In rapid succession his heavy blows rained down, and the sound echoed through the empty house. There was a crash, and the door swung back. They had been so long in almost total darkness that they were blinded for an instant by the dazzling light. And then instinctively they started back, for, as the door opened, a wave of heat came out upon them so that they could hardly breathe. The place was like an oven.

They entered. It was lit by enormous lamps, the light of which was increased by reflectors, and warmed by a great furnace. They could not understand why so intense a heat was necessary. The narrow windows were closed. Dr Porhoet caught sight of a thermometer and was astounded at the temperature it indicated. The room was used evidently as a laboratory. On broad tables were test-tubes, basins and baths of white porcelain, measuring-gla.s.ses, and utensils of all sorts; but the surprising thing was the great scale upon which everything was. Neither Arthur nor Dr Porhoet had ever seen such gigantic measures nor such large test-tubes.

There were rows of bottles, like those in the dispensary of a hospital, each containing great quant.i.ties of a different chemical. The three friends stood in silence. The emptiness of the room contrasted so oddly with its appearance of being in immediate use that it was uncanny. Susie felt that he who worked there was in the midst of his labours, and might return at any moment; he could have only gone for an instant into another chamber in order to see the progress of some experiment. It was quite silent. Whatever had made those vague, unearthly noises was hushed by their approach.

The door was closed between this room and the next. Arthur opened it, and they found themselves in a long, low attic, ceiled with great rafters, as brilliantly lit and as hot as the first. Here too were broad tables laden with retorts, instruments for heating, huge test-tubes, and all manner of vessels. The furnace that warmed it gave a steady heat. Arthur's gaze travelled slowly from table to table, and he wondered what Haddo's experiments had really been. The air was heavy with an extraordinary odour: it was not musty, like that of the closed rooms through which they had pa.s.sed, but singularly pungent, disagreeable and sickly. He asked himself what it could spring from. Then his eyes fell upon a huge receptacle that stood on the table nearest to the furnace. It was covered with a white cloth. He took it off. The vessel was about four feet high, round, and shaped somewhat like a washing tub, but it was made of gla.s.s more than an inch thick. In it a spherical ma.s.s, a little larger than a football, of a peculiar, livid colour. The surface was smooth, but rather coa.r.s.ely grained, and over it ran a dense system of blood-vessels. It reminded the two medical men of those huge tumours which are preserved in spirit in hospital museums. Susie looked at it with an incomprehensible disgust. Suddenly she gave a cry.

'Good G.o.d, it's moving!'