"Not much danger of anything upsetting our calculations from now on," observed Jack, "unless we meet up with drunken punchers, run across some bad men who have been chased by the sheriff's posse out of the railroad towns and who try to make a living by holding up travelers once in six months; or else get caught in a fine old prairie fire." "Say, that last could happen, that's right," Jack went on to exclaim, looking a little uneasily at the dead grass that in places completely concealed the greener growth underneath. "If a big gale was blowing and a spark should get into this stuff she would go awhooping along as fast as a train could run. That's something I've often read about and thought I'd like to see, but come to think of it, now that I'm on the ground, I don't believe I care much about it after all." "They say it's a grand sight," Harry volunteered; "but according to my mind a whole lot depends on which side of the fire you happen to be. What's interesting to some might even mean death to others." "Yes, I've read lots about the same," admitted Jack, "and of the trouble people have had in saving themselves when chased by one of these fires on the plains. If we do see one of the same here's hoping we are to windward of the big blaze." When the sun sank that evening they were hurrying to reach what seemed to be a stream of some sort, judging from the line of trees that cut across the plain and which only grow where there is more or less water to be had. The three burros must have scented the presence of water, for there was no keeping the animals within bounds. They increased their pace until they were almost on the run; and Jimmy threw away the fag end of a whip with which he had been amusing himself by tickling the haunches of the burro in his charge and urging him to move along faster. One of the animals started to bray in a fashion that could have been easily heard half a mile or more away. Hardly had the discordant sounds died away than the boys were considerably surprised to hear a shrill voice coming from directly ahead, as though the exultant bray of the pack animal had given warning of their presence to some one who needed assistance the worst kind. "Help! Come quick and get me! Help--help!" came the words as clear as a bell and causing Harry and Jimmy to stare at each other as though their first thought might have been along the line of some deception that was being practiced upon them. But there was Ned already on the jump and shouting over his shoulder as he ran: "Jimmy, give your burro over to Harry to look after; you too, Jack and follow me on the run!" "That suits me all right!" cried Jack; "here Harry, please look after my pack!" and with these words he was off at full speed.