The boys agreed that after this trip they would be very careful not to go on another mud-sledding expedition.
But soon they came to a long hill, and, going down this, the team began to trot, and Harry and Tom and one or two of the men jumped on the edges of the sled, outside of the load, holding on to the poles.

Then Grits, the big mule, began to run, and Gregory couldn't hold him in, and old Selim and thin Hector and little Polly all struck out on a gallop, and away they went, bumping and thumping down the hill.
And then stick after stick, two sticks, six sticks, a dozen sticks at a time, slipped out behind.
It was of no use to catch at them to hold them on.

They were not fastened down in any way, and Harry and Tom and the men on the sled had as much as they could do to hold themselves on.
When they reached the bottom of the hill the pulling became harder; but Grits had no idea of stopping for that.

He was bound for home.

And so he plunged on at the top of his speed.