’Those are the attics which he uses as a laboratory.  You see, he is working now.  There is no one else in the house.’

Susie was curiously fascinated by the flaming lights.  There was an awful mystery in those unknown labours which absorbed Oliver Haddo night after night till the sun rose.  What horrible things were done there, hidden from the eyes of men?  By himself in that vast house the madman performed ghastly experiments; and who could tell what dark secrets he trafficked in?

‘There is no danger that he will come out,’ said Arthur.  ’He remains there till the break of day.’

He took her hand again and led her on.  Back they went among the trees, and presently they were on a pathway.  They walked along with greater safety.

‘Are you all right, Porhoet?’ asked Arthur.

‘Yes.’

But the trees grew thicker and the night more sombre.  Now the stars were shut out, and they could hardly see in front of them.

‘Here we are,’ said Arthur.

They stopped, and found that there was in front of them a green space formed by four cross-ways.  In the middle a stone bench gleamed vaguely against the darkness.

‘This is where Margaret sat when last I saw her.’

‘I can see to do nothing here,’ said the doctor.

They had brought two flat bowls of brass to serve as censers, and these Arthur gave to Dr Porhoet.  He stood by Susie’s side while the doctor busied himself with his preparations.  They saw him move to and fro.  They saw him bend to the ground.  Presently there was a crackling of wood, and from the brazen bowls red flames shot up.  They did not know what he burnt, but there were heavy clouds of smoke, and a strong, aromatic odour filled the air.  Now and again the doctor was sharply silhouetted against the light.  His slight, bowed figure was singularly mysterious.  When Susie caught sight of his face, she saw that it was touched with a strong emotion.  The work he was at affected him so that his doubts, his fears, had vanished.  He looked like some old alchemist busied with unnatural things.  Susie’s heart began to beat painfully.  She was growing desperately frightened and stretched out her hand so that she might touch Arthur.  Silently he put his arm through hers.  And now the doctor was tracing strange signs upon the ground.  The flames died down and only a glow remained, but he seemed to have no difficulty in seeing what he was about.  Susie could not discern what figures he drew.  Then he put more twigs upon the braziers, and the flames sprang up once more, cutting the darkness sharply as with a sword.

‘Now come,’ he said.

But, inexplicably, a sudden terror seized Susie.  She felt that the hairs of her head stood up, and a cold sweat broke out on her body.  Her limbs had grown on an instant inconceivably heavy so that she could not move.  A panic such as she had never known came upon her, and, except that her legs would not carry her, she would have fled blindly.  She began to tremble.  She tried to speak, but her tongue clave to her throat.