"Arm?" cried Thresk. "What are you talking about?"

Ballantyne looked away from the wall to Thresk, his eyes incredulous.

"But you saw!" he insisted, leaning forward over the table.

"What?"

"An arm, a hand thrust in under the tent there, along the ground reaching
out for my box."

"No. There was nothing to see."

"A lean brown arm, I tell you, a hand thin and delicate as a woman's."

"No. You are dreaming," exclaimed Thresk; but dreaming was a euphemism
for the word he meant.

"Dreaming!" repeated Ballantyne with a harsh laugh. "Good God! I wish I
was. Come. Sit down here! We have not too much time." He seated himself
opposite to Thresk and drew the despatch-box towards him. He had regained
enough mastery over himself now to be able to speak in a level voice. No
doubt too his fright had sobered him. But it had him still in its grip,
for when he opened the despatch-box his hand so shook that he could
hardly insert the key in the lock. It was done at last however, and
feeling beneath the loose papers on the surface he drew out from the very
bottom a large sealed envelope. He examined the seals to make sure they
had not been tampered with. Then he tore open the envelope and took out a
photograph, somewhat larger than cabinet size.