f Mendoza's cavalrymen, who
were moving at a walk along one side of the quadrangle. Alvarez and
Vice-President Rojas, with Stuart, as an adjutant at their side, were
sitting their horses within some fifty yards of the State carriage and
the body-guard. Alvarez made a conspicuous contrast in his black coat
and high hat to the brilliant greens and reds of his generals'
uniforms, but he sat his saddle as well as either of the others, and
his white hair, white imperial and mustache, and the dignity of his
bearing distinguished him above them both. Little Stuart, sitting at
his side, with his blue eyes glaring from under his white helmet and
his face burned to almost as red a tint as his curly hair, looked like
a fierce little bull-dog in comparison. None of the three men spoke as
they sat motionless and quite alone waiting for the next movement of
the troops.

It proved to be one of moment. Even before Mendoza had ridden toward
them with his sword at salute, Clay gave an exclamation of
enlightenment and concern. He saw that the men who were believed to be
devoted to Rojas, had been halted and left standing at the farthest
corner of the plaza, nearly two hundred yards from where the President
had taken his place, that Mendoza's infantry surrounded them on every
side, and that Mendoza's cowboys, who had been walking their horses,
had wheeled and were coming up with an increasing momentum, a flying
mass of horses and men directed straight at the President himself.

Mendoza galloped up to Alvarez with his sword still in salute. His eyes
were burning with excitement and with the light of success. No one but
Stuart and Rojas heard his words; to the spectators and to the army he
appeared as though he was, in his capacity of Commander-in-Chief,
delivering some brief report, or asking for instructions.

"Dr. Alvarez," he said, "as the head of the army I arrest you for high
treason; you have plotted to place yourself in office without popular
election. You are also accused of large thefts of public funds. I
must ask you to ride with me to the military prison. General Rojas, I
regret that as an accomplice of the President's, you must come with us
also. I will explain my action to the people when you are safe in
prison, and I will proclaim martial law. If your troops attempt to
interfere, my men have orders to fire on them and you."

Stuart did not wait for his sentence. He had heard the heavy beat of
the cavalry comin