I began to whistle—­a thing I always do unconsciously when utterly nonplused—­and purposely paid no attention to his words.  I was determined to consider them foolish.

“It wasn’t there last night,” he said presently, straightening up from his examination and looking anywhere but at me.

“We must have scratched her in landing, of course,” I stopped whistling to say, “The stones are very sharp——­”

I stopped abruptly, for at that moment he turned round and met my eye squarely.  I knew just as well as he did how impossible my explanation was.  There were no stones, to begin with.

“And then there’s this to explain too,” he added quietly, handing me the paddle and pointing to the blade.

A new and curious emotion spread freezingly over me as I took and examined it.  The blade was scraped down all over, beautifully scraped, as though someone had sand-papered it with care, making it so thin that the first vigorous stroke must have snapped it off at the elbow.

“One of us walked in his sleep and did this thing,” I said feebly, “or—­or it has been filed by the constant stream of sand particles blown against it by the wind, perhaps.”

“Ah,” said the Swede, turning away, laughing a little, “you can explain everything!”

“The same wind that caught the steering paddle and flung it so near the bank that it fell in with the next lump that crumbled,” I called out after him, absolutely determined to find an explanation for everything he showed me.

“I see,” he shouted back, turning his head to look at me before disappearing among the willow bushes.

Once alone with these perplexing evidences of personal agency, I think my first thought took the form of “One of us must have done this thing, and it certainly was not I.”  But my second thought decided how impossible it was to suppose, under all the circumstances, that either of us had done it.  That my companion, the trusted friend of a dozen similar expeditions, could have knowingly had a hand in it, was a suggestion not to be entertained for a moment.  Equally absurd seemed the explanation that this imperturbable and densely practical nature had suddenly become insane and was busied with insane purposes.

Yet the fact remained that what disturbed me most, and kept my fear actively alive even in this blaze of sunshine and wild beauty, was the clear certainty that some curious alteration had come about in his mind—­that he was nervous, timid, suspicious, aware of goings on he did not speak about, watching a series of secret and hitherto unmentionable events—­waiting, in a word, for a climax that he expected, and, I thought, expected very soon.  This grew up in my mind intuitively—­I hardly knew how.