He knew them by a mark he had taken--where the dog had been first set upon the trail--a small chip broken from one of the fore hoofs.

But Marengo needed not this.

He was once more on the right scent; and again started off, nose down, over the prairie.
Basil leaped into his saddle; and, waving his brother to follow, galloped after, riding close upon the heels of the hound.
The trail did not lead in a direct line.

At some places it did so for several hundred yards--then it would turn suddenly to the right or left--then turn again and again in zig-zag lines.

Sometimes it described the circumference of a circle and at one or two points it recrossed itself.