Jo was convinced that the dust-cloud was raised by horsemen, because of its volume and its rapid advance. That they were enemies was almost certain, since they came from the direction of the angry encampment; and he believed them to be endeavoring to cut off Rob and himself, because otherwise they, too, would be riding across the open fields instead of ploughing through the smothering dust of the gully-like road.
Our lads had allowed their ponies to walk for the last mile or so, but now they urged them forward at a brisk "lope," for they were determined that no man nor body of men from that encampment should get in advance of them if they could help it. Every few seconds one or the other of them glanced over his shoulder at the dust-cloud, to see if they were gaining on it, and finally Rob uttered a shout of: "Here they come, helter-skelter, and enough of them to eat us alive if they catch us! Now we've got to make time. Great Scott! They've got guns, too!"
The horsemen, having discovered that their object was suspected and that their prey was likely to escape, had left the sunken road and now were streaming across the fields in open and hot pursuit. Also, just as Rob glanced back, one of them fired a shot, though where the bullet went to, no one knows. Certainly, it did no harm to our friends, but the shot itself filled them with dismay, as it showed their present pursuers to be better armed than any of the vagrant bands they yet had encountered.
"I believe they are imperial cavalry!" exclaimed Jo. "Yes, I am sure of it," he added, a moment later, as he detected a triangular, yellow pennon fluttering from a lance borne by one of the pursuing horsemen. "They must have been sent out from the city and must have some reason for suspecting us. I wonder if it has become known that we communicated with your mother? That would be a sufficient cause for beheading us both if we are caught, so we must not be."
"I won't be!" declared Rob, clinching his teeth and urging his pony to greater effort. "I'll die first!"
On they swept, mile after mile, over the parched land and under a blazing sun. How they longed for rest and water and shade and coolness; but none of those things were for them so long as that deadly pursuit was kept up. It did not seem to gain on them, but neither did it lose ground. To be sure, some of the cavalry-men straggled, so that they came on in a long, irregular line, but a group of half a dozen leaders kept well together.