“Then, suddenly, for the first time my eyes fell upon Smith.  He was crouching against the wall on my right, in an attitude that was obviously defensive, and it was plain he was in extremities.  The terror on his face was pitiable, but at the same time there was another expression about the tightly clenched teeth and mouth which showed that he had not lost all control of himself.  He wore the most resolute expression I have ever seen on a human countenance, and, though for the moment at a fearful disadvantage, he looked like a man who had confidence in himself, and, in spite of the working of fear, was waiting his opportunity.

“For my part, I was face to face with a situation so utterly beyond my knowledge and comprehension, that I felt as helpless as a child, and as useless.

“‘Help me back—­quick—­into that circle,’ I heard him half cry, half whisper to me across the moving vapours.

“My only value appears to have been that I was not afraid to act.  Knowing nothing of the forces I was dealing with I had no idea of the deadly perils risked, and I sprang forward and caught him by the arms.  He threw all his weight in my direction, and by our combined efforts his body left the wall and lurched across the floor towards the circle.

“Instantly there descended upon us, out of the empty air of that smoke-laden room, a force which I can only compare to the pushing, driving power of a great wind pent up within a narrow space.  It was almost explosive in its effect, and it seemed to operate upon all parts of my body equally.  It fell upon us with a rushing noise that filled my ears and made me think for a moment the very walls and roof of the building had been torn asunder.  Under its first blow we staggered back against the wall, and I understood plainly that its purpose was to prevent us getting back into the circle in the middle of the floor.

“Pouring with perspiration, and breathless, with every muscle strained to the very utmost, we at length managed to get to the edge of the circle, and at this moment, so great was the opposing force, that I felt myself actually torn from Smith’s arms, lifted from my feet, and twirled round in the direction of the windows as if the wheel of some great machine had caught my clothes and was tearing me to destruction in its revolution.

“But, even as I fell, bruised and breathless, against the wall, I saw Smith firmly upon his feet in the circle and slowly rising again to an upright position.  My eyes never left his figure once in the next few minutes.

“He drew himself up to his full height.  His great shoulders squared themselves.  His head was thrown back a little, and as I looked I saw the expression on his face change swiftly from fear to one of absolute command.  He looked steadily round the room and then his voice began to vibrate.  At first in a low tone, it gradually rose till it assumed the same volume and intensity I had heard that night when he called up the stairs into my room.