The cloud passed and a lake of silver spread out to the edge of the coppice, where it terminated at a shadow bank.

“There it is, Petrie!” hissed Nayland Smith.

A lambent light was born in the darkness; it rose slowly, unsteadily, to a great height, and died.

“It’s under the trees, Smith!”

But he was already making for the door.  Over his shoulder: 

“Bring the pistol, Petrie!” he cried; “I have another.  Give me at least twenty yards’ start or no attempt may be made.  But the instant I’m under the trees, join me.”

Out of the house we ran, and over onto the common, which latterly had been a pageant ground for phantom warring.  The light did not appear again; and as Smith plunged off toward the trees, I wondered if he knew what uncanny thing was hidden there.  I more than suspected that he had solved the mystery.

His instructions to keep well in the rear I understood.  Fu-Manchu, or the creature of Fu-Manchu, would attempt nothing in the presence of a witness.  But we knew full well that the instrument of death which was hidden in the elm coppice could do its ghastly work and leave no clue, could slay and vanish.  For had not Forsyth come to a dreadful end while Smith and I were within twenty yards of him?

Not a breeze stirred, as Smith, ahead of me—­for I had slowed my pace—­came up level with the first tree.  The moon sailed clear of the straggling cloud wisps which alone told of the recent storm; and I noted that an irregular patch of light lay silvern on the moist ground under the elms where otherwise lay shadow.

He passed on, slowly.  I began to run again.  Black against the silvern patch, I saw him emerge—­and look up.

“Be careful, Smith!” I cried—­and I was racing under the trees to join him.

Uttering a loud cry, he leaped—­away from the pool of light.

“Stand back, Petrie!” he screamed—­“Back! further!”

He charged into me, shoulder lowered, and sent me reeling!

Mixed up with his excited cry I had heard a loud splintering and sweeping of branches overhead; and now as we staggered into the shadows it seemed that one of the elms was reaching down to touch us!  So, at least, the phenomenon presented itself to my mind in that fleeting moment while Smith, uttering his warning cry, was hurling me back.

Then the truth became apparent.

With an appalling crash, a huge bough fell from above.  One piercing, awful shriek there was, a crackling of broken branches, and a choking groan . . .

The crack of Smith’s pistol close beside me completed my confusion of mind.

“Missed!” he yelled.  “Shoot it, Petrie!  On your left!  For God’s sake don’t miss it!”

I turned.  A lithe black shape was streaking past me.  I fired—­once—­ twice.  Another frightful cry made yet more hideous the nocturne.

Nayland Smith was directing the ray of a pocket torch upon the fallen bough.