Why not use it?
Then, as thoughts come to me in shoals, I next reflected, 'Ah--but this is only one bullet as against sixty-eight birds:' immediately a third thought came, 'why not shoot them all with a single bullet?
It is possible, though not probable.' I snatched out a pad of paper and a pencil, made a rapid calculation based on the doctrine of chances, and proved to my own satisfaction that at some time or another within the following two weeks those birds would doubtless be sitting in a straight line and paddling about, Indian file, for an instant.

I resolved to await that instant.

I loaded my gun with the pearl and a sufficient quantity of powder to send the charge through every one of the ducks if, perchance, the first duck were properly hit.

To pass over wearisome details, let me say that it happened just as I expected.

I had one week and six days to wait, but finally the critical moment came.