and, but for the oppressive heat--"

"Good! You still notice the heat, then," he said to himself, rather than
expecting an answer. "And the lightning?" he added, "that lightning out
of a clear sky--that flashing--did you notice _that_?"

I answered truly that I thought I had seen a flash during a moment of
wakefulness, and he then drew my attention to certain facts before
moving on.

"You remember the sensation of warmth when you put the letter to your
forehead in the train; the heat generally in the house last evening,
and, as you now mention, in the night. You heard, too, the Colonel's
stories about the appearances of fire in this wood and in the house
itself, and the way his brother and the gamekeeper came to their deaths
twenty years ago."

I nodded, wondering what in the world it all meant.

"And you get no clue from these facts?" he asked, a trifle surprised.

I searched every corner of my mind and imagination for some inkling of
his meaning, but was obliged to admit that I understood nothing so far.

"Never mind, you will later. And now," he added, "we will go over the
wood and see what we can find."

His words explained to me something of his method. We were to keep our
minds alert and report to each other the least fancy that crossed the
picture-gallery of our thoughts. Then, just as we started, he turned
again to me with a final warning.

"And, for your safety," he said earnestly, "imagine _now_--and for that
matter, imagine always until we leave this place--imagine with the
utmost keenness, that you are surrounded by a shell that protects you.
Picture yourself inside a protective envelope, and build it up with the
most intense imagination you can evoke. Pour the whole force of your
thought and will into it. Believe vividly all through this adventure
that such a shell, constructed of your thought, will and imagination,
surrounds you completely, and that nothing can pierce it to attack."

He spoke with dramatic conviction, gazing hard at me as though to
enforce his meaning, and then moved forward and began to pick his way
over the rough, tussocky ground into the wood. And meanwhile, knowing
the efficacy of his prescription, I adopted it to the best of my
ability.

The trees at once closed about us like the night. Their branches met
overhead in a continuous tangle, their stems crept closer and closer,
the brambly undergrowth thickened and multiplied. We tore our trousers,
scratched our hands, and