He took the lead in this instance for three reasons: first, we thought that the mule, being much older than the horse, had probably had more experience and therefore might be a much better swimmer; then Field had the advantage in having the life preserver; but the last, and most potent, reason was my fear of getting drowned.

It was understood that I was to remain on shore and be ready to assist him if necessary, or until he had safely landed on the other side.
In he went, and the trusty old mule was swimming faithfully, and had reached the middle of the river, when Field, as he afterwards told me, to hurry the mule, gave a gentle jerk on the bridle, when, to his utter astonishment, the mule made a complete somerset backwards plunging Field, the pack, and himself entirely under the water, except his heels which appeared above the water as his head went under.

In a moment Field popped up and, after shaking his head as a swimmer will do after taking a plunge, cast about to take his bearings, or to determine just where he was, and began to paddle with his hands, much as he did when the canoes were upset on the river, or somewhat after the style of a swimming dog.
On coming to the surface, the mule cast a glance at the still living, but unloaded portion of his cargo, then made a bee line for the shore which he had so recently left.

While Field continued to paddle and float down the river, I dismounted and followed along the bank, trying to encourage him to renewed efforts to float ashore.

Finally he passed behind a clump of willows out of sight; but soon I heard him call for help and on going a little further down, found him stuck fast in the mud.