With the second shot the wire was severed. Telegraph communication between Naocuanha and La Paz was, for the time being, totally interrupted.
"Hope we're not too late," muttered Dacres.
"They may have wired through already. If they have there's ten precious minutes thrown away. Tell the fellow to start her up again, Henri."
As the engine gathered speed Dacres glanced back. The single track was visible for nearly four miles. There were no signs of pursuit from that direction.
Ejecting the cartridge from the magazine of the rifle, the Englishman found that there were still eleven rounds. Having made this reassuring discovery he reloaded, set the weapon carefully in a corner, and devoted his attention to keeping a sharp look-out.
The engine had now gained the foot of the forty-five mile incline up to La Paz. Along this section the danger of being derailed by a loaded truck was not only possible but probable, provided the authorities at La Paz had already been warned. So long as the rail ran in a fairly straight direction there would be ample time to slow down and jump off before the impact occurred; but the fugitives knew that before long the railway would make several sharp and awkward turns.
Soon it became evident that more coal was required. Ordering the engineer to step back and face aft, Dacres plied the shovel while Henri still kept the prisoner covered.
As the vile Lota coal was shovelled into the furnace, clouds of black smoke poured from the squat inverted triangle-shaped funnel, and eddying downwards momentarily obscured the out-look.
The amateur fireman was in the act of throwing on another shovelful when Henri shouted into his ear and with his disengaged arm pointed obliquely in the direction of Naocuanha.
A rift in the pungent cloud of smoke revealed a very unpleasant sight. Overhauling the fugitives, hand over fist, were two large biplanes.