"What is a ratero?" Frank asked.

"He's a thief peculiar to this part of Mexico," was the reply, "or rather, I should say he belongs to the whole country, and the finest quality of him is produced around here. He will open and rob a trunk while carrying it on his back between the hotel and the railway-station; he will cut off the lining of a railway-carriage in less than two minutes, steal railway-ties, and anything else that he can lift; and as for ordinary thefts, his superior cannot be found anywhere. Several years ago the authorities of this town decided to light it with petroleum lamps, but the very first night they did so the lamps were stolen by the rateros, and the town was in darkness as it had been before."

Frank was able to add a few notes to what he and Fred had already ascertained about Mexican thieves. The youths discussed the subject, and came to the conclusion that the tropics produced more adroit pilferers than the temperate zones, at least such had been their experience.

"It is no wonder," said Fred, "that these people have become experts in stealing. Think how they have been despoiled by the Spaniards, who stole their country and all it contained, and reduced the people to the condition of a subject race. No wonder they have sought to revenge themselves on their conquerors, and their mildness of conduct is to be greatly admired, in view of what they have suffered. The condition of a Mexican peon is such that, if I may be permitted the paradoxical statement, he is obliged to steal in order to make an honest living."

Thus musing, they returned to the city with the Doctor and their late companions in the ascent of Popocatepetl.

ANCIENT AZTEC VASES.