"You can't trust that zambo, Jack," he said, decisively; "he might take advantage of your being alone, and knock you on the head."

"Scarcely, when I am armed and he is not. If only we two go, we can travel on the engine. If you all come, I must fix on a carriage."

"Well, that won't make much difference," retorted Philip, quickly. "We are all keen on the business, and want to see how matters turn out. Tim, Peter, Rafael, and myself are all coming with you, Jack; so hitch on a carriage to your engine right away."

This was accordingly done without further objection on the part of Duval, and they left Cuavaca about one o'clock, travelling rapidly so as to reach the terminus with as little delay as possible. According to Pepe, it would take some hours for them to discover the ruined city, and they did not expect to return before six o'clock. Then it would have to be decided whether they would take the troops on to the ruined city at once, or wait till the next day.

Cuavaca was situate at the base of the great volcano Xicotencatl, which reared its white peak high above the surrounding mountains. North and south stretched ranges from the central point with summits more or less covered with snow, and from Cuavaca began dense forests which clothed the slopes of these mighty hills. Leaving the village by the side towards the north, the engine with its solitary carriage ran through a moderately long tunnel piercing a high range of hills, which shot outward at right angles from the principal mountains. From thence it emerged on to a deep valley, and skirted the side of the hills in a winding track cut out of the solid rock. Jack was on board the engine with the driver, personally superintending the journey, and his three friends with Rafael were admiring the view from the windows of the carriage. Pepe, guarded by two soldiers, was seated at the end of the carriage, and looked anything but cheerful under such surveillance.

The scenery was truly wonderful. Sliding along the side of the mountains, those in the carriage looking out, saw not the line on which they were running, but looked down eight or nine hundred feet into the depths below. Sometimes the line was built of solid masonry clamped with iron, and it was anything but pleasant to think how the train was clinging like a fly to the perpendicular sides of the giant hills. Below swirled rapid torrents raging over black rocks, or flowing in broad streams between flat mud-banks. The engine would proceed along a level for some distance, then pant slowly up an ascending gradient; suddenly turning a sharp curve, she would shoot breathlessly down a decline on to a long narrow bridge thrown across a wide expanse of river bed intersected by thin streams, which at time of rain joined their forces into one vast flood. Owing to the infinite windings of the line, it was built on the narrow gauge system, so as to permit the quick turning of curves, and when the engine, leaning to one side, shot round these turnings, the sensation was anything but pleasant.

"It's a most wonderful line, so far as engineering goes," said Philip, drawing back from the window with a sudden qualm, as the carriage rocked dangerously; "but it is devilishly unpleasant. If we went over!"

"There wouldn't be much of us left," said Tim grimly. "Begad, Philip, I've been in a mighty lot of railway trains, but this line of Jack's beats Banagher, and Banagher beats the devil."

"Santissima!" said Rafael, uneasily, "I trust, Señores this devil of an engine will not fall over the cliff."

"I'd never travel on this line for pleasure," cried Peter, who was seated on the opposite side to the precipice for safety; "nor do I think it will be much patronised by people when opened."