Billie and Adrian paid no attention to his cry, whereupon he also put spurs to his horse, leaving the peons gaping with astonishment in the middle of the road.
And now the boys came into sight of the water front where the fighting was going on. It was at the instant that the order had been given to clear the space around the custom house, and the boys saw the marines advance on the double quick.
The Mexicans gave way, but volley after volley was poured down upon the advancing Americans from the roofs of houses and from nearby church towers.
There were several shots in rapid succession from the Chester, which had drawn in more closely, every one of which struck a tower where a large force of Mexicans had gathered.
The tower toppled and fell, carrying many with it.
"Hurrah!" cried Billie. "Give it to them!" and, firing his rifle as he went, he rode right down into the main street.
"He'll be killed by our own men!" cried Donald.
But he was not. Instead he dashed into the open space in front of the custom house, just as the marines swept by, his hat off and his rifle cracking as fast as he could fire.
Seeing that the danger from the marines was past, Donald and Adrian fell in behind Billie, just as an officer came around the corner at the head of another company.
Espying the boys, he halted his command.