In “The Border Boys Across the Frontier” they were found aiding Uncle Sam. They happened to find a strange subterranean river by means of which arms and ammunition were being smuggled to Mexican revolutionists. In trying to put a stop to that work they were captured, and escaped only after a ride on a borrowed locomotive and a fight in the stockade of the Esmeralda mine. We now find them in San Mercedes awaiting the arrival of the Texas Rangers, a detachment of whom had been ordered to the little settlement on the banks of the Rio Grande Del Norte to put down any disturbances, and to keep the warring Mexicans from committing outrages on Uncle Sam’s soil. The boys, always anxious for anything that might offer in the way of adventure, had begged their fathers to allow them to see something of the work of the Rangers. At first this had been absolutely refused. But finally Mr. Stetson gave his permission, and then Mr. Merrill fell in line, as did Walt Phelps’ parents. Captain Moseby Atkinson of the Rangers being an old friend of Mr. Merrill’s, the rest was easy, and it had been arranged that the boys were to meet Captain Atkinson at San Mercedes. Though they looked only for fun and novel experiences, the Border Boys were destined, while with the Rangers, to pass through adventures more thrilling, and hardships more severe than they dreamed. On dashed the Rangers, the hoofs of their mounts thundering like artillery. It was a sight calculated to stir the heart and quicken the pulse of any wholesome, active lad. There were fully twenty of them, riding six abreast. Their sombreros, blue shirts, rough leather chaps and the rifles slung in each man’s saddle holster, showed them to be men of action in the acutest sense of that word; men whose bronzed faces and keen, steady eyes bespoke them of the best type of plainsman; worthy descendants of Fremont, Lewis and Clarke. “Yip! Yip!” the foremost of the riders shouted as they saw the boys. Jack’s fiery little pony began to show signs of frantic alarm. It bucked and tried to throw itself backward, but each time the young horseman’s skill checked it. “Captain! Captain!” called Jack, as the Rangers swept by. But above the thunder of hoofs, and in the midst of the yellow dust clouds, Captain Atkinson did not hear nor see the two boys. But one of his men, a rather squat, dark–skinned, dark–haired little fellow, did. “Y—e—ow! Out of the way, you tenderfoot kid!” he exploded. “I’m trying to get out of the way,” responded Jack good humoredly. “What’s that, you long–legged cayuse,” bellowed the little chap, whose sleeves were tied round above the elbows with gorgeous pink ribbons, and whose black silk shirt was embroidered with pink rosebuds, “what’s that? Can you ride, kid? Can you ride?” At the same instant Jack’s pony swung around, presenting its flank toward the little Ranger. As it did so the Texan brought down his quirt with all its force on the startled little creature’s rump.