For myself, though I could not be certain, I came to the conclusion that whoever had used the place had done so not many days before.

It could not have been quite recently; but it may not have been very long ago.

Whoever had used it had covered up his tracks well.

Even the ashes had been carefully removed, and the place where they had lain was cleaned or swept in some way, so that there was no trace on the spot.
I applied some of my West African experience, and looked on the rough bark of the trees to leeward, to where the agitated air, however directed, must have come, unless it was wanted to call attention to the place by the scattered wood-ashes, however fine.

I found traces of it, but they were faint.