The boys told him that they were going down to the river to fish for eels, and Marco's soul was all on fire to accompany them.

He had never fished for eels.
He knew the boys very well, and they offered to lend him a hook and line.

But Marco thought that on the whole it would not do.

He tried to persuade them to wait until the afternoon, but they would not consent to such a postponement of their pleasure.

So Marco wished them good luck, and began to mount the fence again, with the intention of returning to his studies.
On looking toward the office, he saw his uncle coming out of the door in the rear of it, and walking toward the house.