For the sight of the mirror, loosely wired so that it faced the foot of the grave, immediately brought into my mind the first line of that bewildering doggerel:
"Flimmer', flimmer' viel."
The reference to flashing surely indicated that the mirror was to be used as a heliograph. The next line—that about "the garrison of Kiel"—still utterly floored me; but, I reflected, since we had a heliograph, the following lines which I surmised to give a compass bearing of 27 degrees ("The Feast of Orders" i.e., Jan. 27), might well furnish the direction in which—for reasons still unknown to me—the sun's rays were to be flashed. The wiring of the mirror to the timber indicated the direction in which the bearing was to be taken. It looked to me as though the Unknown must have set up his own cross and wired the mirror to it before he died.
I opened the little leathern case which hung at my belt and drew out my prismatic compass, trusty friend of my campaigning days in France. The grave faced practically due north. I laid the compass on the mirror and took a bearing of 27 degrees. The white arrow on the floating centre of the compass swung round. The mark of the 27th degree pointed towards a gaunt and barren pile of rock on the far side of the crater. I took as my line of direction a tall bush aflame with some gorgeous flower on the edge of the clearing.
Some cautious instinct made me detach the mirror. Holes had been bored on either side of the frame through which strands of copper wire were passed and knotted to holes bored in the timber cross-piece. I removed wire and all and slipped the mirror into my pocket. Garth did not notice the action; for he was busy pottering about the clearing. From the luxuriant undergrowth he ultimately collected a cigar box which, I made no doubt, was the identical one from which the man Dutchey had established the fact that Black Pablo and his friends had visited the island. It was curious to find everything in the same state as it had been left more than a year ago. I felt rather like a man must feel who violates a grave.
"There's a path beyond," Garth said, pointing over to the left. "It leads to the spring. I found an old bucket on the bank. But otherwise there's no sign of our Unknown friend here. In fact the whole place looks as if it had been undisturbed since the flood. Whew! but it's hot! Okewood, I believe we're going to have a storm!"
The air was indeed strangely oppressive. The patch of sky which thatched the clearing was now flecked with daubs of white cloud and there was a curiously menacing stillness in the atmosphere. On trees and bushes the leaves hung motionless without a tremor. We sat down to cool off a bit.
"It doesn't look too good to me," I answered. "Garth, I shouldn't wonder if we were in for a soaking to-night!"
Sir Alexander Garth, Bart., who had never slept out in the rain in his life, smiled in rather superior fashion.
"I shouldn't wonder," he returned. "As a matter of fact, I rather like roughing it. It's a devilish healthy life, my boy! What's the next move? Has the grave given you any ideas for the location of the treasure?"