Suddenly the casus belli, as usually happens, arose of its own accord.

The last but one of the chained line was an old gray-headed man, followed by a slender graceful girl of some eighteen years old, and Amyas’s heart yearned over them as they came up.  Just as they passed, the foremost of the file had rounded the corner above; there was a bustle, and a voice shouted, “Halt, senors! there is a tree across the path!”

“A tree across the path?” bellowed the officer, with a variety of passionate addresses to the Mother of Heaven, the fiends of hell, Saint Jago of Compostella, and various other personages; while the line of trembling Indians, told to halt above, and driven on by blows below, surged up and down upon the ruinous steps of the Indian road, until the poor old man fell grovelling on his face.

The officer leaped down, and hurried upward to see what had happened.  Of course, he came across the old man.

“Sin peccado concebida!  Grandfather of Beelzebub, is this a place to lie worshipping your fiends?” and he pricked the prostrate wretch with the point of his sword.

The old man tried to rise:  but the weight on his head was too much for him; he fell again, and lay motionless.

The driver applied the manati-hide across his loins, once, twice, with fearful force; but even that specific was useless.

“Gastado, Senor Capitan,” said he, with a shrug.  “Used up.  He has been failing these three months!”

“What does the intendant mean by sending me out with worn-out cattle like these?  Forward there!” shouted he.  “Clear away the tree, senors, and I’ll soon clear the chain.  Hold it up, Pedrillo!”

The driver held up the chain, which was fastened to the old man’s wrist.  The officer stepped back, and flourished round his head a Toledo blade, whose beauty made Amyas break the Tenth Commandment on the spot.

The man was a tall, handsome, broad-shouldered, high-bred man; and Amyas thought that he was going to display the strength of his arm, and the temper of his blade, in severing the chain at one stroke.

Even he was not prepared for the recondite fancies of a Spanish adventurer, worthy son or nephew of those first conquerors, who used to try the keenness of their swords upon the living bodies of Indians, and regale themselves at meals with the odor of roasting caciques.

The blade gleamed in the air, once, twice, and fell:  not on the chain, but on the wrist which it fettered.  There was a shriek—­a crimson flash—­and the chain and its prisoner were parted indeed.

One moment more, and Amyas’s arrow would have been through the throat of the murderer, who paused, regarding his workmanship with a satisfied smile; but vengeance was not to come from him.

Quick and fierce as a tiger-cat, the girl sprang on the ruffian, and with the intense strength of passion, clasped him in her arms, and leaped with him from the narrow ledge into the abyss below.